# Found Decade Old Flash Paper, Flash Cotton And Smoke Powder- Are They Still Safe To Ignite? **URL:** \ **Category:** Factual Questions\ **Created:** [October 6, 2022, 12:36am UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791 "2022-10-06T00:36:29Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![DocCathode](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/doccathode/32/18773_2.png) [@DocCathode](https://boards.straightdope.com/u/DocCathode)\ **Post date:** [October 6, 2022, 12:36am UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/1 "2022-10-06T00:36:29Z")
I know from personal experience that old fireworks are NOT safe to ignite- (short version the explosive chemicals separate and instead of a fountain of sparks you get a big boom). IIRC old sparklers simply won’t ignite. But what about the substances I named? ---
**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 6, 2022, 1:33am UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/2 "2022-10-06T01:33:36Z")
Flash paper and flash cotton are names for nitrocellulose. Smokeless power is another name, not sure what ‘smoke powder’ refers to. Flash powder is a pyrotechnic mixture most firecrackers are made from as well as other fireworks, and user for very old flash photography. Different formulas were used, but commonly a mix of aluminum and potassium perchlorate. It is more dangerous and likely to spontaneously ignite and explode than nitrocellulose even when newly made. The problem with nitrocellulose degrading is instability. It may ignite more easily than before or spontaneously. Uncontained it will produce flames. But how easily they ever ignited depended on the actual form and their intended usage. ---
**Author:** ![Kedikat](https://avatars.discourse-cdn.com/v4/letter/k/ed655f/32.png) [@Kedikat](https://boards.straightdope.com/u/Kedikat)\ **Post date:** [October 6, 2022, 1:43am UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/3 "2022-10-06T01:43:40Z")
It is most likely to be less energetic when/if it combusts. But as noted, it may be more unpredictable as to force, heat, required to initiate combustion. I would definitely store them in a steel container if you plan to keep them. Cool place. Away from other things. ---
**Author:** ![DocCathode](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/doccathode/32/18773_2.png) [@DocCathode](https://boards.straightdope.com/u/DocCathode)\ **Post date:** [October 6, 2022, 2:07am UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/4 "2022-10-06T02:07:45Z")
Thanks, I generally store all nitro cellulose in a metal mummy case (I’ll post a picture later). I’m not sure what to transfer the powder to. ---
**Author:** ![Kedikat](https://avatars.discourse-cdn.com/v4/letter/k/ed655f/32.png) [@Kedikat](https://boards.straightdope.com/u/Kedikat)\ **Post date:** [October 6, 2022, 2:18am UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/5 "2022-10-06T02:18:58Z")
If the powder isn’t already in a glass container, I would transfer it to one and then in a steel container. Like an ammo box. What is this stuff and the flash paper wrapped / stored in now? Curious what the manufacturer sent it in. ---
**Author:** ![DocCathode](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/doccathode/32/18773_2.png) [@DocCathode](https://boards.straightdope.com/u/DocCathode)\ **Post date:** [October 6, 2022, 2:56am UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/6 "2022-10-06T02:56:59Z")
The flash paper came in little cardboard booklets. The flash cotton came in a paper pouch. The powder came in a grew plastic bottle with screw on plastic lid. ---
**Author:** ![Kedikat](https://avatars.discourse-cdn.com/v4/letter/k/ed655f/32.png) [@Kedikat](https://boards.straightdope.com/u/Kedikat)\ **Post date:** [October 6, 2022, 3:07am UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/7 "2022-10-06T03:07:48Z")
I would just keep them in those containers then. But in a steel ammo box. I worry most about the flash paper and cotton. I suspect they are most likely to self combust. Meant to easily ignite with just a little added energy. Got any fun ideas for using them? I would have burned it all up so fast. No worries of storage. You must have good self control. ---
**Author:** ![DocCathode](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/doccathode/32/18773_2.png) [@DocCathode](https://boards.straightdope.com/u/DocCathode)\ **Post date:** [October 6, 2022, 3:10am UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/8 "2022-10-06T03:10:07Z")
I have a spark ring I bought at the same store. Just wrap a little flash cotton around the flash paper and you appear to throw flames 3 feet long. ---
**Author:** ![Kedikat](https://avatars.discourse-cdn.com/v4/letter/k/ed655f/32.png) [@Kedikat](https://boards.straightdope.com/u/Kedikat)\ **Post date:** [October 6, 2022, 3:34am UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/9 "2022-10-06T03:34:02Z")
There are some who call me…Tim… ---
**Author:** ![Edward\_The\_Head](https://avatars.discourse-cdn.com/v4/letter/e/ce73a5/32.png) [@Edward\_The\_Head](https://boards.straightdope.com/u/Edward_The_Head)\ **Post date:** [October 6, 2022, 12:26pm UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/10 "2022-10-06T12:26:36Z")
I got some flash paper for Halloween a few years ago. After about two years it would not really ignite. Not sure if stuff that’s a decade old will work at all. ---
**Author:** ![DocCathode](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/doccathode/32/18773_2.png) [@DocCathode](https://boards.straightdope.com/u/DocCathode)\ **Post date:** [October 6, 2022, 4:48pm UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/11 "2022-10-06T16:48:59Z")
[[Album] Sarcophagus ![](https://i.imgur.com/0PzaWFf.jpeg?fb "Sarcophagus") ](https://imgur.com/gallery/lMYI1l8) Here’s a shot of the tin I keep my nitrocellulose in. ---
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [October 6, 2022, 5:19pm UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/12 "2022-10-06T17:19:06Z")
Unsafe! I found that out years ago in a spectacular fashion when an entire storage house outside of my home town was blown into the sky but what investigators determined to be, “sweating dynamite”, termed as such because the “sweat” was actually nitroglycerin that was leeching out of the dynamite due to advanced age. ---
**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 6, 2022, 5:23pm UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/13 "2022-10-06T17:23:49Z")
He doesn’t have dynamite or nitroglycerin. Well Ilmaybe he does but he didn’t mention it here. ---
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [October 6, 2022, 5:24pm UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/14 "2022-10-06T17:24:30Z")
I understand that, but the principle is the same; i.e., separating components causing instability. ---
**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 6, 2022, 5:31pm UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/15 "2022-10-06T17:31:25Z")
Not with nitrocellulose. It can become unstable but the materials he has wouldn’t explode. They could start a serious fire but he’s been cautioned to keep these materials in fireproof containers. Nitrocellulose products mentioned may absorb enough moisture over time that they won’t ignite, someone mentioned that happening with flash paper. I have encountered flash paper that would barely ignite when new though, it’s not all the best stuff. ---
**Author:** ![Steven\_Maven](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/steven_maven/32/3272_2.png) [@Steven\_Maven](https://boards.straightdope.com/u/Steven_Maven)\ **Post date:** [October 7, 2022, 3:30am UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/16 "2022-10-07T03:30:59Z")
As a life-long amateur magician, my educated guess is that ancient flash paper is safe if you follow the usual precautions, and will produce an effect close to a fresh piece. Start with a small sample, say the size of your thumbnail. It is very mild. There is no comparison to “sweating dynamite.” Once I intentionally ignited a moderate piece on my palm and did not get even slightly burned. I am not familiar with flash cotton. ---
**Author:** ![Kropotkin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kropotkin/32/18045_2.png) [@Kropotkin](https://boards.straightdope.com/u/Kropotkin)\ **Post date:** [October 7, 2022, 11:52pm UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/17 "2022-10-07T23:52:35Z")
Wasn’t there a magician/flash paper maker who blew himself up transporting a bunch of it in his car several years ago? Unlikely to be relevant to the OP’s situation, but still, be careful out there ---
**Author:** ![Elmer\_J.Fudd](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/elmer_j.fudd/32/1211_2.png) [@Elmer\_J.Fudd](https://boards.straightdope.com/u/Elmer_J.Fudd)\ **Post date:** [October 8, 2022, 12:39am UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/18 "2022-10-08T00:39:00Z")
Alas, I’m in the “only one way to know for sure” camp when it comes to stuff like this. My hearing isn’t the best but I still have all my fingers. ---
**Author:** ![DocCathode](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/doccathode/32/18773_2.png) [@DocCathode](https://boards.straightdope.com/u/DocCathode)\ **Post date:** [October 9, 2022, 7:01pm UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/19 "2022-10-09T19:01:53Z")
I have heard credible stories of flash paper left in glove compartment igniting on hot day and burning up maps and insurance papers ---
**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 11, 2022, 2:15pm UTC](https://boards.straightdope.com/t/found-decade-old-flash-paper-flash-cotton-and-smoke-powder-are-they-still-safe-to-ignite/972791/20 "2022-10-11T14:15:29Z")
Sounds like a great opportunity for an SDMB experiment in an open field. Gather all your suspect materials in a pile and remotely ignite them all. With cameras recording from a suitable worst-case distance. I can’t see the upside to carefully storing increasingly unstable flammables in a stout container. Agree this stuff is not dynamite, so inadvertantly turning your ammo can into an IED is implausible. But since the only possible outcome is some shade of bad, why bother? So that 10 years from now when you rediscover the forgotten ammo can you can ask us about the safety of 20-year-old flash-stuff? ISTM the only way to win this game is not to play.