I'm improving my bathroom and pulled up the old linoleum and two layers of old vinyl tile only to come to a material over the plywood that seems like really sticky Henry's roof sealant. I think it was used to adhere the first layer of tiles. I want to prep the floor and fill the cracks and level out the subfloor before I put on my new vinyl. Does this black material have to come of first and if so what might be the best way?

I have been scraping and doing more damage to the floor and then I tried just a test spot with orange hand cleaner. Any help is appreciated.

Thanks

I would just add a layer of 1/4 inch luan you will never get that subfloor clean enough.

Sorry guys, luan is not recommended for a wet area like a bathroom. Old school idea no longer used. We use Hardibacker 1/4" cement board or wonder board for wet applications. Screw it and glue it and it will be there when they through dirt on you.