Yes, toothpaste can be used as a grout cleaner. Toothpaste has a bleaching component in it that removes stains and dirt. However, you have to make sure that the toothpaste is white and it mustn’t be a gel product. Cleaning your grouting with toothpaste may take longer because you have to apply the product and start scrubbing immediately. It’s a cheaper alternative to using grout cleaner but certainly not the easiest. Grout cleaner draws all the dirt and bacteria out of your grouting simply by leaving it on the surface for five to 10 minutes. When using a proper grout cleaner, you don’t have to do any vigorous scrubbing because the detergent has done half the work for you. So if you really don't have any other products left at home to clean your grouting then toothpaste will be an adequate alternative.