hi guys just come round a silly little problem,which is,im working on site and using vitra 1-6 white grout and wen it comes to polishing up the grout is hard to come off,ived used this grout many of times and never had a prob, the tiles im working with is a glazed tile and the other one is a matt finish tile,i leave the tiles for bout 2hrs till they are ready to buff up so i need to know wots going on or has anybody had the same probs as me many regards dave