How to Safely (and not so safely) Dispose of Oil-Soaked Rags
QUESTION: The safety quiz on FineWoodworking.com says to put oil/finish soaked rags in a covered metal container. Isn’t it better to allow the volatiles to evaporate in a well-ventilated area first, so as to avoid spontaneous combustion or explosion? – via Knots
For those of you who are unaware of the safety hazards associated with oily rags in the shop, news reports about shop fires started by improperly stored oil-soaked rags are common place. And it’s always the same story, a wadded up oily rag combusts and leads to a total-devistation fire (as seen in the YouTube video above and described in detail in Chris Minick’s article in Fine Woodworking issue #177.)
Safe home-shop solutions
As many astute readers pointed out in the Knots forum, the answer we provide in the quiz of storing your oil-soaked rags in an airtight metal container only works if you subscribe to a service that collects those oily rags for proper disposal.
“Unless proper removal and disposition facilities are available, you have just post-poned the problem,” writes Steve Schoene in the Knots forum. “The OSHA regulation that talks about this 29 CFR 1926.252(e) clearly means this as a temporary measure ‘until removed from worksite.'”
Our recommended solution pretty much excludes the common home woodworking enthusiast who would find a rag-collection service an unrealistic option. So what’s the alternative?
“The final solution,” Steve writes, “requires either destruction by something like burning, or a safe way to let the material cure without cumulating heat. For home and small commercial shops, the easiest way is to spread the rags in a single layer so heat dissipates while the material cures. Then, depending on local regulations, the materials can be safely disposed of, either in hazardous waste collection sites, or in the general landfill.”
UPDATE: To answer the comment below, an oily rag has cured when it becomes hard and brittle. The time it takes to cure can vary considerably depending on humidity, temperature, and the finish.
Mike Hennessy is one of several who follow a similar solution: “I usually lay my old rags out flat on the ground outside to dry. That way, not enough heat can build up.” Another reader replied that he incinerates them in the wood stove.
I have to admit, while I helped write our new safety quizzes using our library of expert texts as resources, I typically dispose of my oily rags by hanging them over the edge of a trash can until they dry, and then throw them in the trash. Time to go write a new quiz question, I guess.