Redoing bathroom floors and under the tiles there was really old carpet. I was able to remove the upper layer of it, but there is a tar-like substance stuck on the wooden floor that is very difficult to remove. Are there any tricks or chemicals that can be used to easily peel this away and leave the wood intact?
I just wet it with soap and hot water, maybe a few times over the course of a half hour, and then use a wallpaper scraper.
I used paint remover and a stiff 4" wide putty knife, it worked for me very well. I laid it on thick, let it set for a while and the knife scraped it right up. My bathroom is about 50 sq ft floor area, it took 2 quarts to get it done. After that I sanded the area with my random orbit sander and a vacuum attached to it to make sure it was a smooth surface and insure the floor was clear of contaminates.
A carbide paint scraper was my tool of choice for the black carpet adhesive residue that stuck to my floors. With a steel scraper it was nearly pointless; the carbide stayed sharp enough, long enough, to work on my particular variant of black glop, so I did not have to pull up and replace the floor to get a clean surface. I did not use any chemicals, as I had a large area to do and it would have ben a lot of chemicals.
A mastic remover is available that is nontoxic and it smells like oranges, but I can't for the life of me recall the name. But it is a citrus base and nonflammable.