When Rags Go Bad: how rags can burst into flames and try to kill you

If you’ve ever done any refinishing (furniture, wood floors, etc.) you’ve likely heard the warnings—leave the rags you’ve used lying around and you could have a house fire. So what’s the deal? How do perfectly innocent rags (or newspapers for that matter) turn into incendiary bombs ready to burn down your garage or home?

Simply put there are certain materials that are subject to “spontaneous heating. They don’t need an external heat source to warm up and catch fire. Among those materials are several common oils. That means rags or pieces of newspaper (like the kind you set underneath grandma’s chair while you are working on refinishing it) that have absorbed linseed oil (or cod-liver oil, but who puts that on wood floors—can you imagine the smell?), when left to their own devices increase in temperature without drawing heat from their surroundings. Cue the fire-engines.

It’s worth noting that spontaneous heating is NOT spontaneous combustion—it is SCARIER.

In spontaneous combustion (and wood does this—no seriously, innocent, everyday wood), you need a high external temperature, and then, when the exposed material reaches a certain core temperature, it ignites. For example, most “new” wood will combust at exposure to temperatures between 392 and 500 degrees Fahrenheit. But in spontaneous heating the temperature in the surrounding location is not the trigger—it doesn’t matter if that box of rags is in your nicely airconditioned basement, they can still erupt into flames and try to kill you.

Want to watch a scary video showing EXACTLY this? ABC news did a report on the phenomenon, and it’s chilling . . . At 1 hour into their experiment the crumpled paper and rags in their box had reached 100 degrees (don’t worry the video skips the wait, and tells the whole terrifying tale in under 2 minutes). Two hours in and the box is smoking. At a little over three hours—FIRE!!!!

I’ve said it before, and I’ll say it again . . . my search history is SCARY.


  1. Colin Conway on April 24, 2022 at 12:13 pm

    Hi Evie –

    Great post and thank you for the video link, too! Holy cow. Very scary. Makes for all sorts of story ideas.

    • Evie Hawtrey on May 19, 2022 at 10:54 am

      It sure does. And also nightmares. There is NO chance I am refinishing anything here at home in the future! I will send furniture out so if someone’s place burns it is NOT mine.

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