It is always best to start with the mildest cleaning approach. When it comes to cleaning grout, that means to begin by washing it first. You may find this step removes most of the mess in minutes.
The easiest way to wash your grout is with a bowl of hot, soapy water and a scrub brush. Dip the brush into the soapy water then rub in circles along the grout line. Spray with clean water to rinse. If your grout still needs work, the next step explains how to make a homemade grout cleaner.
Apply Homemade Grout Cleaner
In a bowl, combine 2 parts baking soda and 1 part of hydrogen peroxide. Add a small amount of liquid dish detergent. (For example, mix 3/4 cup of baking soda and 1/4 cup hydrogen peroxide with 1 teaspoon of liquid dish detergent.)
Using the corner of a rag, apply this homemade cleaner to the grout.
Wait 15 minutes and then scrub along the grout line with an old toothbrush.
Spray with hot water to rinse and wipe with a clean rag. Spot treat any remaining grout stains using the methods in the next step.
Remove Grout Stains
Safety tip: Be sure you have thoroughly rinsed your tile and grout well before proceeding. It's not safe to combine cleaning products, even those used in homemade grout cleaners. (Related: Cleaning Ingredients You Must Never Mix.)
Make a homemade grout stain remover:For white grout, use 2 tablespoons chlorine bleach stirred into 2 cups of water. Do not use this on anything but white grout, though, since it can leach the color.For tinted or colored grout, replace chlorine bleach with an oxygenated bleach cleaner. (Oxiclean is one brand. Several store brands also work well. Look for the terms 'oxygen cleaner' or 'oxygenated bleach.')
Apply the stain remover to your grout with a rag and wait 15 minutes for it to work.
Dip a sponge or rag into the remaining solution and scour the grout line. Rinse well with clean water.
If you discover greasy residue on your grout, a little rubbing alcohol on the corner of a rag should clean it right up.
Keep your grout sealed to protect it. Always clean your grout first then let it dry at least 24 hours before you apply sealant. Use a sponge or small brush to apply sealer along the grout lines. Wipe excess away with a damp rag immediately, or it will cause a permanent haze on your tile. Reseal grout between wall tiles every year and between floor tiles every six months.