I would like to put ceramic or porcelein tile on my concrete family room floor. I've removed the tile and about 90% of the mastic. Does 100% of the mastic need to be removed from the whole floor before thinset can be used to start tiling. I'm getting mighty discouraged as the mastic is not easy to remove. Is a floor leveler a good idea? I found the citrus based mastic remover much easier to use than the bean goo, FYI. Thanks for any help.