I've been cautious with old rags from boiled linseed oil, but never seen so much as a smoulder...
I read a while back about a home-mix 'Danish' oil, which was a blend of boiled linseed (which has already had things done to it to persuade it to dry faster than raw linseed, which might not dry at all) and natural turpentine. I bought some of the latter - it smells nice. I suppose I ought to try it on something.