What is a natural cleaner for grout?

Water, baking soda, lemon juice, and vinegar can be mixed together to form a solution for cleaning grout. Another solution is a mixture of hydrogen peroxide and water.

For the baking soda and vinegar solution, mix seven cups of water, 1/2 cup of baking soda, 1/3 cup of lemon juice, and 1/4 cup of vinegar in a bucket. Use a cleaning rag to apply the cleaning solution to the grout. Let it sit for 60 seconds, then scrub with a bristle brush. For the hydrogen peroxide solution, mix 1 part hydrogen peroxide and 1 part water in a spray bottle. Spray the grout until saturated and wait 45 minutes. Wipe with a sponge and rinse.