Good Evening
I've just had a new bathroom installed including blacky grey porcelain wall tiles. I've been using it for about 2 weeks but I'm starting to see lots of grey blobs popping up on the tiles. What is this substance and how do I get rid of it. It looks the same colour as the grout but I'm not sure if that is what it is, as it seems to be appearing over time.
Is there anyway of remedying this easily? I'm trying to contact the company who did the installing but also wanted to get some independent advice.
