There's no doubt your tile grout will get dirty over time, whether from everyday use or mildew. There are a variety of grout-cleaning products available on the market; however, most require you to apply the cleaner then scrub. Make your own no-scrub grout cleaner to get your grout sparkling clean without the hassle of scrubbing.
Fill an empty 32 oz. spray bottle with 3 1/2 cups of water, 1/4 cup baking soda, 1/8 cup white vinegar and 3 tbsp. household ammonia. Put on the lid and shake to mix.
Spray the mixture onto the dirty grout until it's saturated. Let it sit for five minutes.
Wipe the liquid from the grout with a damp rag.