A Victorian Plumbing expert said: “Toilet cleaner contains high levels of powerful acidic chemicals and using this solution can cause damage to tile grout. “Instead, use a diluted bleach solution - and don’t forget to wear protective gloves and open a window.” If you are struggling with more stubborn grout stains, you might want to consider using a strong cleaning product designed for grout. There are plenty of products designed for grout on the market and in supermarkets. Trending How do you clean a shower? Once you have scrubbed the grout, you’ll probably want to get the rest of your shower sparkling too.