I've read that you can install ceramic tile over old flooring. We pulled up the top layer of vinyl tiles in the bathroom and found an old - probably 40's - layer of linoleum. We *started* to pull that up, but underneath is a thick, sticky tar-like residue (I've read it may contain asbestos). So we only pulled up (chisled away actually) about 4-5 squares. Now we're wondering - do we have pull up all the old linoleum? If so, how can we get rid of the tar adhesive? Do we have to put down concrete board or something under the new tile? I want to do it right but don't want to make extra work for ourselves! Any tips are appreciated!