Old tile adhesive/grout?
I have some large format tiles to lay, couple whole tiles and some cut sections to finish of a job someone left unfinished 5/6 years ago. The bags of tile adhesive and grout have been in bin bags under the stairs since, some feel a little hard but will crumble if needed. Does this stuff go off? I have never tiled before, its a floor, but I learn well from you tube etc. Its only finishing off etc so considering trying the last couple of bits myself. Floor is level and ready, large format porcelain, grout black, will need to get/borrow tile splitter