Spot test the cleaner on the grout. Before you dive right into cleaning the grout with the toilet cleaner, you should spot test it first on a portion of the grout. Choose a spot that can be covered up or hidden if it gets damaged. Use a small amount of the toilet cleaner on the grout and leave it on for five minutes. If the grout does not appear damaged, you can proceed to use the toilet cleaner on the rest of the grout.
Pour the cleaner on the grout and let it sit. Do this by pouring the cleaner on the area with grout that is furthest from the door. This way, you can clean the grout in small sections, moving towards the door and cleaning each section as you go. If you are cleaning grout along a bathtub or a faucet, you do not have to worry about doing this.
Pour a small amount of the cleaner on the grout. Do not pour too much cleaner on the grout or lay it on too thickly. You want an even amount dispersed on the grout so the cleaner can soak in and remove any dirt or grime. Allow the cleaner to stay on the dirty grout and soak in for five minutes. Do not touch or disturb the cleaner when it is sitting on the grout.
Scrub the grout with a toothbrush. Once you have let the cleaner sit on the grout, take a toothbrush or a grout cleaning brush, and gently run it over the grout. You should not have to scrub the cleaner off the grout very hard to remove any grime or dirt. Often, the grime will come off easy by running the brush over the grout.
Scrub all of the grout that is covered with the cleaner. You should notice the grout appears clean and grime-free once you scrub it with the brush. Rinse and dry the grout well. It is very important that you rinse off the toilet cleaner as soon as you are done scrubbing the grout with the brush. Do not let the cleaner sit on the tile or the grout once you are done scrubbing it, as this can lead to a built up of residue.