slate

I am planning to put natural slate tile on concrete slab floor in the house. I removed the original 1957 9"x9"vinyl tiles and I am left with traces of the original black glue everywhere. The question is. Can I lay the new slate tiles (using standard adhesive thin set) directly over the concrete covered with this old black glue? The area is approx. 70sf and I am trying to avoid grinding the glue off the concrete or using an adhesive chemical remover.
Please help!
Thanks, Paul C.

Sorry Paul, you have to get it to look like fresh new concrete. Just kidding.

Prep the floor by wetting one area at a time and giving it a quick scrape with a 4" razor scraper to knock off any loose adhesive rsidue, vacuum it up with a shop vac and move on to the next area. When you are done, and you are left with just a staining on the slab, you can go right over it with any thinset that says it can be used over "cutback adhesive." At HD, that would be Flexbond, and at Lowes, that would be Multipurpose Pro.

If there are any cracks in the slab, that would require further attention, so post back, otherwise, good luck.

Brian