Can Used Gun Cleaning Rags Spontaneously Combust?

**Walleye Hunter** · September 18th, 2018, 12:50 PM

Spontaneous combustion of oil soaked rags is a real phenomenon but can it happen with our gun solvents? This issue rings louder with me because I lived near a solvent factory as a kid and the thing went up every couple of years. As I finish up with my gun cleaning rags I seal them up in a glass bottle for now but I don't really know enough about the solvent I'm using (Hoppe's #9) to know if it's an issue or not. I looked around a little and didn't find an answer to this one. What sayeth ye?

**bogey1** · September 18th, 2018, 01:03 PM

I dont know if it would with gun cleaning solvents but I wouldnt leave them soaked in my house.
I was on a job in ridley creek state park last year where the house behind the house I was working on burned to the ground overnight.
The guys stripping paint from a deck left the rags in a can on the deck. The only thing standing was the stone chimney.
Put the rags in a ammo box or wet them.

**Aggies Coach** · September 18th, 2018, 01:04 PM

Funny you should bring this up. I wash all my gun and car cleaning rags/towels right after I use them. Particularly because I waa wondering about that myself.

**MARINE DIVISION TWO** · September 18th, 2018, 01:10 PM

Maintenance Dept of our Patrol Vessels was guilty of this and occasional oil rag fire was an occurence too frequently !

**Sparks** · September 18th, 2018, 01:12 PM

This usually happens with boiled Linseed oil, which is a drying oil, and a pile of rags, or if they are confined.

However, error on the safe side.

**MT1** · September 18th, 2018, 01:17 PM

You're combining two totally different compounds in one question. Oil and solvents are not the same. To answer the question you also have to understand the true definition of spontaneous combustion.

According to the web the definition of spontaneous combustion (spontaneous ignition) is a type of combustion which occurs by self-heating (increase in temperature due to exothermic internal reactions), followed by thermal runaway (self heating which rapidly accelerates to high temperatures) and finally, auto ignition.

In your case neither gun oils or gun solvents are self heating. If you toss them in a dryer at a very high temperature you would potentially create the right atmosphere for ignition. Most cases of what is assumed to be spontaneous combustion are ignited by spark. The case of the solvent factory you mention... this was most likely a situation where the LEL (lower explosive limit) is present meaning the particulate concentration, O2 level, etc are perfect and just need a spark or flame to ignite. The conditions must be just right with the airborne concentration falling between the LEL and UEL (upper explosive limit). When I was a kid I had a friend who's family owned a large saw mill. The saw dust collection system was prone to this and resulted in several fires over the years.

Materials only spontaneously combust when there is a heat source. As long as your rags aren't near a heater, flame, extreme sun... you're ok.

**Walleye Hunter** · September 18th, 2018, 01:30 PM

MT1, a lot of that makes sense to me. From what I have been able to dig up I found that the substances in question need to oxidize as they sit and the process of oxidation causes the temps to rise to the point of ignition, then spontaneous combustion will occur. I also saw something about an iodine index that identifies an oil or solvent's propensity to oxidize.

There was a time when I was young and ummm less knowledgeable than I am today and I was puffing away on my pipe in a grain shed while taking a break from filling bags of oats with a shovel. Darwin was on break that day.