eeb, try using whiting or kitty litter along with much longer low heat. It may have taken decades for oil to soak deep into the wood, and it takes a long time to bring much of it back to the surface. I've heard of people building a solar oven but find that a vehicle parked in the sun in the summer will easily reach 160 degrees, and you can do it for a week or more for only the cost of the absorbent material.

Voting for anti-gun Democrats is dumber than giving treats to a dog that shits on a Persian Rug