oily rags and spontaneous combustion

[lph]

Short story - yes, it happens. Be VERY careful with rags (or laundry) with a lot of oil on them, be it bike oil or anything else.

Long story: my BIL applied some furniture oil to some tables and left them out on the rooftop terrace to dry, on a hot day. He had heard of spontaneous combustion in oily rags, and put the rag in a metal bucket for safety, also outdoors. Somehow the entire shebang ignited anyway, and burnt like a torch. The fire blew in the window, and set the sprinkler system going. His (brand new, just moved in, lovely penthouse...) apartment is now soaked in water, covered in soot, everything reeks of smoke and most of his belongings are ruined. The cat made it, but inhaled some smoke. It will be 4-6 months before the place is habitable again. The water soaked all the way through to the ground, 6 floors below.

I have now learnt that oily rags should either be burnt immediately, or hung up to dry, or immersed in water. Just wanted to be sure that noone else I know has to experience this!