Stir in the rest of the ingredients until it forms a thick paste.
Scoop a generous amount onto the brush, and scrub into the grout to loosen the dirt.
Wipe clean with a cloth or sponge.
Notes
If you have a large room with a lot of grout to clean, then you may need to double or triple this recipe.
This recipe is meant for one-time use. Leftovers will not save well and should be discarded.
An old electric toothbrush or an electric cleaning brush will make scrubbing easier and more effective.
Add a small soft scrub brush attachment to the end of a drill to make a heavy-duty, strong grout-cleaning brush. This trick is especially good for large rooms.
For highly stained or dirty tile grout, allow the cleaner to sit for 10-20 minutes before scrubbing.
Allow the grout to airdry or put a fan on it to help it dry faster after cleaning. For best results, avoid stepping on the grout until it's completely dry.
Lemon essential oil is very helpful for dealing with tough stains on the grout or tile. For extra cleansing power, add a drop onto a stain and let it sit for a few minutes before cleaning it with the grout cleaner.