It do go way back, I believe Mr Wizzard showed an example on his show. Course I think it was a rag with Mineral Spirits or something that goes through an Endomorphic reaction while drying. Back in 93 we had a little October surprise that killed just tons of trees with snow damage. So our city had collection points where they turned all the wood into wood chips. Mountains of them. 3 of which caught fire when the chips started to decompose. Hey, if my 4 x 4 x 4 compost pile can get hot enough to steam on a early spring day, what else could catch on fire.