After about 10 years, it’s time to replace the vinyl floor in our kitchen.  In Houston, these floors are glued to the concrete slab, probably using a suitable vinyl flooring mastic.  For durability and aesthetics, my wife and I have decided to replace the old vinyl flooring with a ceramic tile floor.  (We’ve done numerous home projects before, including a tile floor on a “virgin” cement floor.  We used thinset mortar and had no problems with the project, with the possible exception of sore legs and knees!)  On this project, my first step will be to use an ice scraper (we’re former Yankees) to remove the vinyl flooring material from the slab, followed by a thorough cleaning of the remaining glue with scrapers or single edge razor blades in holders.  (I know that this will be tedious, but I wanted to remove as much glue as possible.)  I would assume, however, that a thin “film” of glue will be left on the slab…  What do you suggest that I use for an adhesive for the ceramic tile to the slab?  Will thinset properly bond to the slab if there is a film of glue on the slab, or will we have to use a special adhesive for the tiles?  Although the slab will not flex, the kitchen is a “high traffic” area, and I would hate to have the tiles come loose from the slab.  Any help is deeply appreciated.