# How do mirrors retain anything that's written on them? **URL:** \ **Category:** Factual Questions\ **Created:** [October 22, 2011, 5:32am UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426 "2011-10-22T05:32:00Z")\ **Posts on this page:** 19\ **Page:** 1
**Author:** ![Gy273](https://avatars.discourse-cdn.com/v4/letter/g/d07c76/32.png) [@Gy273](https://boards.straightdope.com/u/Gy273)\ **Post date:** [October 22, 2011, 5:32am UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/1 "2011-10-22T05:32:00Z")
I’m sure many people have had this occurrence say when they have to wipe the steam off and the next day or so they see the streak marks. Sorry if this is a dumb question but as they saying goes “The only stupid questions are those not asked.” But still how does that work exactly? My only theory is that it has something to do with the grease on my fingers but I could be wrong. Thanks for the answers in advance. 🙂 ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [October 22, 2011, 6:34am UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/2 "2011-10-22T06:34:14Z")
You guessed right. The oils in your fingers are hydrophobic. But they stick well to glass. So, if steam or frost condenses on the surface of the glass, it’ll accumulate in different concentrations, depending on the distribution of oils, or other contaminates on the surface of the glass making the oils or streaks much more visible. ---
**Author:** ![Noel\_Prosequi](https://avatars.discourse-cdn.com/v4/letter/n/b19c9b/32.png) [@Noel\_Prosequi](https://boards.straightdope.com/u/Noel_Prosequi)\ **Post date:** [October 22, 2011, 11:13am UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/3 "2011-10-22T11:13:53Z")
Reminds me of a mate who, while still living at home but while his parents were away, had a one night stand with a girl he picked up, and the “Adult Cuddles” were held in the parental bed. He (being a complete cad) ushered her out hurriedly when it was all over, only to discover that she had written her phone number in lipstick on the mirror in his parents’ bathroom. He was very proud he had wiped it all off, until I reminded him that lipstick is full of fats and the like, and the next time one of his parents had a shower, the number would pop up again in the condensation on the mirror. His parents were terrifyingly formidable, and watching him have shower after shower in a blind panic, testing every cleaning product he could to get even the remnants out of the mirror, made me laugh so hard I think I let out a little bit of wee. To answer the question, I have heard it said that the surface of glass is macroscopically very smooth but microscopically pitted so that the waxes etc in fingers and lipstick fill the pits in a way that is difficult to remove, and consequently alters the way condensation adheres to the surface. ---
**Author:** ![jjimm](https://avatars.discourse-cdn.com/v4/letter/j/ba8739/32.png) [@jjimm](https://boards.straightdope.com/u/jjimm)\ **Post date:** [October 22, 2011, 11:23am UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/4 "2011-10-22T11:23:46Z")
Whenever I remove someone’s kidneys and leave them in a bath of ice, I use lipstick. ---
**Author:** ![Mahaloth](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mahaloth/32/1079_2.png) [@Mahaloth](https://boards.straightdope.com/u/Mahaloth)\ **Post date:** [October 22, 2011, 1:24pm UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/5 "2011-10-22T13:24:32Z")
> [@jjimm](#): > > Whenever I remove someone’s kidneys and leave them in a bath of ice, I use lipstick. You leave the kidneys in a bath of ice? Weird. 😉 ---
**Author:** ![postcards](https://avatars.discourse-cdn.com/v4/letter/p/8e8cbc/32.png) [@postcards](https://boards.straightdope.com/u/postcards)\ **Post date:** [October 22, 2011, 2:26pm UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/6 "2011-10-22T14:26:53Z")
> [@jjimm](#): > > Whenever I remove someone’s kidneys and leave them in a bath of ice, I use lipstick. > [@Mahaloth](#): > > You leave the kidneys in a bath of ice? Weird. > > 😉 Weirder still, he seems to remove the kidneys with the lipstick. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [October 22, 2011, 3:20pm UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/7 "2011-10-22T15:20:52Z")
Reminds me of that Linda Rondstadt song with the line “… put another notch in my lipstick case…” Damn fierce she was. Feircer than we all knew, apparently. A man-killer with an appetite for kidneys. Showbiz is full of weirdos. ---
**Author:** ![kayaker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kayaker/32/441_2.png) [@kayaker](https://boards.straightdope.com/u/kayaker)\ **Post date:** [October 22, 2011, 3:34pm UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/8 "2011-10-22T15:34:10Z")
Every time I stay in a hotel, I write, “I’m watching you” on the bathroom mirror steam. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [October 22, 2011, 5:11pm UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/9 "2011-10-22T17:11:16Z")
You are most evil. May I subscribe to your newsletter? At the very moment I’m killing time in a hotel & will soon take a shower & then start my workday. Thanks to \*kayaker \*I now have a plan … ---
**Author:** ![kayaker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kayaker/32/441_2.png) [@kayaker](https://boards.straightdope.com/u/kayaker)\ **Post date:** [October 22, 2011, 6:02pm UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/10 "2011-10-22T18:02:28Z")
Hey, if only once you cause someone to have a _The Shining_ type moment, it is worth it. 😃 ---
**Author:** ![jjimm](https://avatars.discourse-cdn.com/v4/letter/j/ba8739/32.png) [@jjimm](https://boards.straightdope.com/u/jjimm)\ **Post date:** [October 22, 2011, 10:59pm UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/11 "2011-10-22T22:59:30Z")
> [@postcards](#): > > Weirder still, he seems to remove the kidneys with the lipstick. Very sharp, lipstick. I put the kidneys in ice so they don’t spoil. :smack: ---
**Author:** ![BrotherCadfael](https://avatars.discourse-cdn.com/v4/letter/b/977dab/32.png) [@BrotherCadfael](https://boards.straightdope.com/u/BrotherCadfael)\ **Post date:** [October 22, 2011, 11:10pm UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/12 "2011-10-22T23:10:04Z")
> [@LSLGuy](#): > > Reminds me of that Linda Rondstadt song with the line “… put another notch in my lipstick case…” You misspelled Pat Benatar. ---
**Author:** ![code\_grey](https://avatars.discourse-cdn.com/v4/letter/c/f4b2a3/32.png) [@code\_grey](https://boards.straightdope.com/u/code_grey)\ **Post date:** [October 22, 2011, 11:38pm UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/13 "2011-10-22T23:38:23Z")
is there a standard solution to this, like washing the mirror with alcohol? What should the hotel do to counter such vandalism? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [October 23, 2011, 12:31am UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/14 "2011-10-23T00:31:00Z")
Windex and similar products will do the job. ---
**Author:** ![kayaker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kayaker/32/441_2.png) [@kayaker](https://boards.straightdope.com/u/kayaker)\ **Post date:** [October 23, 2011, 2:04am UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/15 "2011-10-23T02:04:20Z")
> [@code\_grey](#): > > is there a standard solution to this, like washing the mirror with alcohol? What should the hotel do to counter such vandalism? Who you calling a vandal, bitch? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [October 23, 2011, 3:47am UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/16 "2011-10-23T03:47:31Z")
Well, this oughta get interesting. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [October 26, 2011, 2:49pm UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/17 "2011-10-26T14:49:44Z")
> [@BrotherCadfael](#): > > > [@LSLGuy](#): > > > > Reminds me of that Linda Rondstadt song with the line “… put another notch in my lipstick case…” > > You misspelled Pat Benatar. Good catch. Those two sorta smoosh together in my head. Haven’t thought about either for years. ---
**Author:** ![Triskadecamus](https://avatars.discourse-cdn.com/v4/letter/t/b19c9b/32.png) [@Triskadecamus](https://boards.straightdope.com/u/Triskadecamus)\ **Post date:** [October 26, 2011, 3:15pm UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/18 "2011-10-26T15:15:41Z")
> [@LSLGuy](#): > > Good catch. Those two sorta smoosh together in my head. Haven’t thought about either for years. Now I am thinking about Pat Benatar, and Linda Rondstat all smooshed together in the shower. I am still thinking about it. Tris ---
**Author:** ![EvilTOJ](https://avatars.discourse-cdn.com/v4/letter/e/ee59a6/32.png) [@EvilTOJ](https://boards.straightdope.com/u/EvilTOJ)\ **Post date:** [October 27, 2011, 6:28am UTC](https://boards.straightdope.com/t/how-do-mirrors-retain-anything-thats-written-on-them/600426/19 "2011-10-27T06:28:57Z")
> [@kayaker](#): > > Every time I stay in a hotel, I write, “I’m watching you” on the bathroom mirror steam. I do this too. Or I write “I love you” and a giant heart around it.