# what's the best way to both kill and repel cockroaches? **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [June 29, 2011, 4:42pm UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275 "2011-06-29T16:42:06Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![brietex73](https://avatars.discourse-cdn.com/v4/letter/b/da6949/32.png) [@brietex73](https://boards.straightdope.com/u/brietex73)\ **Post date:** [June 29, 2011, 4:42pm UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/1 "2011-06-29T16:42:06Z")
Dear Cecil, In one of your other posts you said to mix borax, flour and cocoa powder to get rid of roaches, is there a different agent i could use other than cocoa powder so that its not so noticable? -šŸ˜•C.S. * * * LINK TO COLUMN: [Whatā€™s the best way to kill cockroaches? - The Straight Dope](http://www.straightdope.com/columns/read/20/whats-the-best-way-to-kill-cockroaches) ---
**Author:** ![Ignatz](https://avatars.discourse-cdn.com/v4/letter/i/3be4f8/32.png) [@Ignatz](https://boards.straightdope.com/u/Ignatz)\ **Post date:** [June 30, 2011, 2:09am UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/2 "2011-06-30T02:09:23Z")
a. More borax b. leave a dead one lying around (unless you are having guests). It repels them (both the roaches and the guests). ---
**Author:** ![Lucretia](https://avatars.discourse-cdn.com/v4/letter/l/13edae/32.png) [@Lucretia](https://boards.straightdope.com/u/Lucretia)\ **Post date:** [July 1, 2011, 2:25am UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/3 "2011-07-01T02:25:12Z")
You need a pest control company. Yeah, yeah, not earth-friendly, blah blahā€¦for really effective roach control, you really, really need a professional company. When I found roaches in my home, I would have offered any freaky thing the pest control guy wanted to get rid of them, but all he wanted was a body of the roach (Um, yeah, smashed into atoms, sorry), or a good description. Never saw any after that. Worth every penny. ---
**Author:** ![Powers](https://avatars.discourse-cdn.com/v4/letter/p/edb3f5/32.png) [@Powers](https://boards.straightdope.com/u/Powers)\ **Post date:** [July 1, 2011, 6:29pm UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/4 "2011-07-01T18:29:14Z")
> [@Lucretia](#): > > When I found roaches in my home, I would have offered any freaky thing the pest control guy wanted to get rid of them, but all he wanted was a body of the roach (Um, yeah, smashed into atoms, sorry), or a good description. Never saw any after that. Worth every penny. I assume he also wanted said pennies, then, not just a corpse? Powers &8^] ---
**Author:** ![Lucretia](https://avatars.discourse-cdn.com/v4/letter/l/13edae/32.png) [@Lucretia](https://boards.straightdope.com/u/Lucretia)\ **Post date:** [July 2, 2011, 12:09am UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/5 "2011-07-02T00:09:19Z")
> [@Powers](#): > > I assume he also wanted said pennies, then, not just a corpse? > Powers &8^] Hehā€¦yes, he did want those. Although, not as many as I orginally thought, nor would have been willing to pay, honestly. ---
**Author:** ![brynnnnn](https://avatars.discourse-cdn.com/v4/letter/b/cc9497/32.png) [@brynnnnn](https://boards.straightdope.com/u/brynnnnn)\ **Post date:** [July 6, 2011, 3:28am UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/6 "2011-07-06T03:28:05Z")
Iā€™m surprised nobody mentioned pandan leaves. People leave them everywhere here balconies, bathrooms, car boots. I moved from the 20th floor to the 3rd floor a few years back, and evidently that was close enough to the ground for the buggers to get in, because I had them walk in and fly in way too regularly to my taste. However, ever since I put a pandan plant on my balcony and pandan leaves on my window ledge, the numbers have gone down to maybe 1 cockroach per several months. Then again, I have a cicak behind the fridge thatā€™s twice the size of any normal cicakā€¦ ---
**Author:** ![EvilTOJ](https://avatars.discourse-cdn.com/v4/letter/e/ee59a6/32.png) [@EvilTOJ](https://boards.straightdope.com/u/EvilTOJ)\ **Post date:** [July 7, 2011, 7:08am UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/7 "2011-07-07T07:08:48Z")
diatomaceous earth is a good substance to have around the house. Itā€™s ground up diatom shells and theyā€™re wickedly sharp on a microscopic level. It works into the carapaces of insects and kills them by cutting them to death. ---
**Author:** ![davidm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/davidm/32/225_2.png) [@davidm](https://boards.straightdope.com/u/davidm)\ **Post date:** [July 8, 2011, 1:37am UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/8 "2011-07-08T01:37:03Z")
I understand it can also cut up your lungs if you get the wrong kind. > **[Diatomaceous earth | Safety considerations](https://en.wikipedia.org/wiki/Diatomaceous_earth#Safety_considerations)** > > Inhalation of crystalline silica is harmful to the lungs, causing silicosis. Amorphous silica is considered to have low toxicity, but prolonged inhalation causes changes to the lungs. Diatomaceous earth is mostly amorphous silica but contains some crystalline silica, especially in the saltwater forms. In a 1978 study of workers, those exposed to natural diatomaceous earth for over five years had no significant lung changes while 40% of those exposed to the calcined form had developed pneu The cry... ---
**Author:** ![EvilTOJ](https://avatars.discourse-cdn.com/v4/letter/e/ee59a6/32.png) [@EvilTOJ](https://boards.straightdope.com/u/EvilTOJ)\ **Post date:** [July 8, 2011, 5:18am UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/9 "2011-07-08T05:18:09Z")
Well duh, just donā€™t get any under your carapace and youā€™ll be fine :eyeroll: The kind used for gardens available by the bag in gardening sections is safe for us to use. ---
**Author:** ![kamnet](https://avatars.discourse-cdn.com/v4/letter/k/6de8d8/32.png) [@kamnet](https://boards.straightdope.com/u/kamnet)\ **Post date:** [July 8, 2011, 10:09pm UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/10 "2011-07-08T22:09:03Z")
Take your boric acid/borax/Roach Prufe and mix it with corn syrup (3 tbsp of syrup to 1 tbsp of powder), mix it up and put it in or on a disposable surface (piece of cardboard, Styrofoam bowl, etc). Make sure thereā€™s no other food or water around. You donā€™t need more than a spoonful or so, this stuff will last for a few weeks. Roaches will flock to it like candy, attracted by the corn syrup. Eventually the liquid will evaporate and it will harden, but you can keep adding small parts of corn syrup to keep it fresh if necessary. ---
**Author:** ![karent](https://avatars.discourse-cdn.com/v4/letter/k/f19dbf/32.png) [@karent](https://boards.straightdope.com/u/karent)\ **Post date:** [July 11, 2011, 12:52am UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/11 "2011-07-11T00:52:05Z")
> [@kamnet](#): > > Take your boric acid/borax/Roach Prufe and mix it with corn syrup (3 tbsp of syrup to 1 tbsp of powder), mix it up and put it in or on a disposable surface (piece of cardboard, Styrofoam bowl, etc). Make sure thereā€™s no other food or water around. You donā€™t need more than a spoonful or so, this stuff will last for a few weeks. Roaches will flock to it like candy, attracted by the corn syrup. Eventually the liquid will evaporate and it will harden, but you can keep adding small parts of corn syrup to keep it fresh if necessary. Thatā€™s a great idea ! ! ! Iā€™m going to go try it. Thanks ---
**Author:** ![John\_Stamos\_Left\_Ear](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_stamos_left_ear/32/3198_2.png) [@John\_Stamos\_Left\_Ear](https://boards.straightdope.com/u/John_Stamos_Left_Ear)\ **Post date:** [December 28, 2018, 3:30pm UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/12 "2018-12-28T15:30:06Z")
Cecilā€™s column (which he just published on the Straight Dope Facebook page which is what brought it to my attention) is literally from over a third of a century ago! Surely in all that time we have developed new roach-busting technology that puts goopy borax paste to shame. ---
**Author:** ![Beckdawrek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beckdawrek/32/3647_2.png) [@Beckdawrek](https://boards.straightdope.com/u/Beckdawrek)\ **Post date:** [December 28, 2018, 3:50pm UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/13 "2018-12-28T15:50:29Z")
Cleanliness is the only way. No standing water, no food stuffs, Including pet food left out. We have a bug man who sprays a barrier outside the house and close outbuildings. My house is a log cabin. A magnet for all critters. The best thing I have going is NO neighbors. My biggest problem is centipedes. I really hate, hate those things. Eeecckk. ---
**Author:** ![glowacks](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/glowacks/32/5548_2.png) [@glowacks](https://boards.straightdope.com/u/glowacks)\ **Post date:** [December 29, 2018, 5:41pm UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/14 "2018-12-29T17:41:13Z")
This is now the title of the front page column, but the link leads to the column [The millennium approacheth. Will it start Jan. 1, 2000, or Jan. 1, 2001? - The Straight Dope](https://www.straightdope.com/columns/read/120/the-millennium-approacheth-will-it-start-jan-1-2000-or-jan-1-2001/) I assume that the main link originally worked since this got bumped, but apparently the link was updated for a different column but the graphic and text were not. ---
**Author:** ![eastcheap](https://avatars.discourse-cdn.com/v4/letter/e/8491ac/32.png) [@eastcheap](https://boards.straightdope.com/u/eastcheap)\ **Post date:** [December 29, 2018, 10:00pm UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/15 "2018-12-29T22:00:01Z")
> [@Beckdawrek](#): > > My biggest problem is centipedes. I really hate, hate those things. Eeecckk. Theyā€™re probably feeding on something worse. Itā€™s a conundrum. ---
**Author:** ![Beckdawrek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beckdawrek/32/3647_2.png) [@Beckdawrek](https://boards.straightdope.com/u/Beckdawrek)\ **Post date:** [December 29, 2018, 10:10pm UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/16 "2018-12-29T22:10:42Z")
Ho-ly crap, now I have to look for other critters! Thx so much, I kinda hate you;) My cats are good at letting me know when something is moving about. They were fixated on a window sill the other day. I went with flyswatter and paper towel in hand to find a tiny little, sweet red and black spotted lady bug. I was gonna ease it out the window and wish it well when the bastard flew up in my face. I proceeded to kill it, forthwith. Dead, I tell you. All. Gone. ---
**Author:** ![TubaDiva](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tubadiva/32/507_2.png) [@TubaDiva](https://boards.straightdope.com/u/TubaDiva)\ **Post date:** [December 31, 2018, 2:04am UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/17 "2018-12-31T02:04:24Z")
> [@glowacks](#): > > This is now the title of the front page column, but the link leads to the column [The millennium approacheth. Will it start Jan. 1, 2000, or Jan. 1, 2001? - The Straight Dope](https://www.straightdope.com/columns/read/120/the-millennium-approacheth-will-it-start-jan-1-2000-or-jan-1-2001/) > > I assume that the main link originally worked since this got bumped, but apparently the link was updated for a different column but the graphic and text were not. A tiny coding error ā€¦ called for #120 inistead of #20. Fixed now. Sorry about that. Jenny your humble TubaDiva Administrator ---
**Author:** ![guizot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guizot/32/3636_2.png) [@guizot](https://boards.straightdope.com/u/guizot)\ **Post date:** [December 31, 2018, 2:34am UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/18 "2018-12-31T02:34:30Z")
Donā€™t use just Borax as it is sold. The issue, I believe, is that the way it is sold, itā€™s not a very fine powder, but thatā€™s what you need so that the insects canā€™t avoid it. I assume thatā€™s part of the reason for mixing it with something. So if someone just buys Borax and uses it as is, it might not have much effect. There are products which are versions of boric acid in a fine powdered form, whichā€“for me at leastā€“have worked well. One was the ā€œMiraculous Insecticide Chalk,ā€ which was outlawed by the EPA. It was powdered boric acid (Borax) compressed into a chalk stick. You could draw lines of it on floors, walls, etc., so that you could make inescapable perimeters for the roaches. In other words, you could apply it strategically and not have to get all over the place. The EPA outlawed it solely because it resembled chalk, and the assumption was that children would therefore eat it. However, there are many other products which are fine powder versions of Borax, which you just squirt or dust. Itā€™s not as convenient as the ā€œMiraculous Insecticide Chalk,ā€ but has the same effect. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [December 31, 2018, 5:14am UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/19 "2018-12-31T05:14:53Z")
> [@guizot](#): > > Donā€™t use just Borax as it is sold. The issue, I believe, is that the way it is sold, itā€™s not a very fine powder, but thatā€™s what you need so that the insects canā€™t avoid it. I assume thatā€™s part of the reason for mixing it with something. So if someone just buys Borax and uses it as is, it might not have much effect. Cecil mentions that Borax works by: > [@](#): > > 1. The stuff gets on the waxy coating on the critterā€™s hide (or ā€œexoskeletonā€) and partially dissolves it, whereupon the cockroach dehydrates and croaks. > > 2. The borax acts as an abrasive, causing microscratches in said coating. Cockroach dehydrates, etc. Sure sounds to me like how diatomaceous earth works so why not just use that? If you get the food quality DE (which is what you want) it is so safe you can eat it with no ill effect (just do not inhale itā€¦it is fine lying around but donā€™t snort it). Basically it is made of the ground up shells of diatoms and it scrapes the hell out of insect exoskeletons. It takes some time to work compared to poisons but it is not poison so for a long term solution it is a good bet. Cheap too. Most gardening centers will sell it. ---
**Author:** ![guizot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guizot/32/3636_2.png) [@guizot](https://boards.straightdope.com/u/guizot)\ **Post date:** [December 31, 2018, 6:39am UTC](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275/20 "2018-12-31T06:39:14Z")
> [@Whack-a-Mole](#): > > Cecil mentions that Borax works by: . . . Yeah, I never contradicted that. To repeatā€“the problem is that Borax is not a finely ground powder, so itā€™s easier for the roaches to avoid the particles. Other forms of boric acid which are more powdery work better. Thatā€™s the point. > [@Whack-a-Mole](#): > > Sure sounds to me like how diatomaceous earth works so why not just use that? Thatā€™s fine, too. Boric acid is even cheaper, though, if you know where to buy it. Both substances do more or less the same thing. [Next page](https://boards.straightdope.com/t/whats-the-best-way-to-both-kill-and-repel-cockroaches/587275.md?page=2)