Our contractor cleaned our tile well, but left instructions to use vinegar and water at a certain point - two hours? two days? after the grouting was done. I recently redid the grout in our walk-in shower, so took particular care since it is a problem that appears often on ahr. Not difficult at all to remove the grout. Just don't let the darn stuff dry, and if you use unglazed tile, I believe they need to be sealed before they are installed. RTFL.