I want to replace coloured grout in my bathroom with white grout. But the original grout is really hard and tough. I've tried scraping it but had very little luck.. Any ideas???
No easy answer I'm afraid - whether you use a Dremmel or do it by hand it's a real pain in the bum job that takes a lot of time and leaves you with aching arms. If you're not bothered about a really neat finish the take the top 1-2 mm off then apply the white grout over the top. Good luck!