In article et,
Richard Lamb wrote:

While on that subject, can some olde-timer tell me something about oily
rags and spontaneous combustion?

Mostly an issue for linseed oil soaked rags (generally a woodworking or
painting related item), as linseed oil is a "drying" oil (it oxidizes
and gets hard). That reaction gives off heat. Put that reaction in a
nice, well-insulated location like a pile of rags, and you get fires
that start by themselves, especially since the reaction is faster when
it's hotter, so it puts out more heat, which makes it faster...

Option 1 is to avoid it (and walnut oil, and tung oil) completely.

Option 2 is not to use rags.

Option 3 is to use rags, put them in a ziploc, and put that in the
freezer.

Option 4 is to use rags, and toss them in a woodstove on on an open
fire when done.

Option 5 is to use rags, and dry them out flat - on the floor in a
single layer, on a clothesline, etc - some way that heat cannot build up.

Option 6 is to use rags and place them in a bucket of water

etc...

You can still get double-wall oily rag safety cans (which are supposed
to be emptied every night) that have a tight lid sealing the rag area
(to limit oxygen supply) and the double walls help to keep anything else
from catching if the rags start burning.

As far as I know, a motor or machine oil soaked rag is a great thing for
some other ignition source to start a fire with, but is not likely to
start up on its own.

--
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