yes we have stripped slate floor, one of the biggest problems that people face when stripping slate is that, the natural colour of slate is light grey, this has a treatment put on in the factory process that darkens it dramatically, or colours it, dependent, if you have an almost black, charcole effect colourant on the slate and you take it off when stripping, which is most likely then to re-colour get a small bucket add a little sealent a little blackboard paint and mix, take a sponge, dip it in squeeze out the excess and re colour the floor, taking care not to touch the grout line as theese are often light in colour, and hey presto the slate floor is returned to original colour. reseal in normal way.
regards Dave ADL