I use domestos when I have to. Just squirt it all over the place (lol) and leave it for about 4 hours.
Just make sure the windows and exhaust fan are on!

If that is a little harsh though, get yourself some white vinegar and some bicarb and make a paste, and a toothbrush, a hard one, and go to town....a PITA but it is pretty effective.

I think you can get some stuff at a hardware store that is like grout paint...it goes on like white out and can match to just about any colour grout. Fairly cheap too.


But tell the man to take his $500 and...well, you know! lol