Home depot makes a grout cleaner in a large orange bottle, it's amazing. Spray on, wait 2 minutes and wipe clean. It's also excellent at cleaning tiles with texture or divets.
After cleaning though, you would want to seal the grout, with a grout sealant to prevent the problem from reoccuring! ... View related article.
Home Depot sells a non-toxic grout cleaner made from oranges. Spray on, wait 2 minutes, scrub clean. You'd want to seal the grout after the cleaning though to prevent the problem from reoccuring, which of course isn't going to be non-toxic. lol ... View related article.
We redo a lot of investment properties ourselves, when I first heard about the product I was super excited. Having picked up whats available in the local DIY stores and doing my research online- The best and only brand to get is Aqua-Mix. Which is available for online order if its not in a store near you.
It comes in a wide variety of colors. They also offer a kit. However it's cheaper just to get the paint and cleaner.
Some advice- if you get the kit DO NOT USE the enclosed toothbrush like applicator to apply the paint, it's far too course and creates unfixable brush strokes. I found that cheap artist brushes are better than any of the applicators that are also sold in stores.
FOLLOW ALL THE INSTRUCTIONS!!!, especially the cleaning and prep, and clean up of excess. If you do the result is excellent.
If you are trying to cover dark grout, then don't bother with the grout paint. We tried once and it ended up taking 4 days. We were working on making a grey grout white. It took 3 coats on one test wall and with the tedious application, dry time and clean up of excess in between coats it was much faster, easier & cheaper just to dig out a little bit of the grout with a removal tool and regrout in white & seal. ... View related article.
They make grout cleaners. You can pick them up at your local DIY store. Kelvin is right in that you should avoid the acids. There is a brand made in an orange bottle, and it works excellent, spray on, wait 2 minutes, srub off.
After that dries you should then seal the grout with a grout sealant to prevent the problem from happening again. ... View related article.