Grout whitener and decalcifying gel are two products used on your grout to remove some of the impurities and to re-establish its white shine. Below, these two products are discussed further.
Tile Grout Whitener
You can purchase tile grout whitener in any local home improvement center. Use this whitening product when you want to restore the white look of your grout. It is a great way to even give your grout a light seal.
When you use a grout whitener, you want to make sure that you scratch the surface of the grout before you apply the whitener. This helps to make sure the whitener penetrates into the older grout, seals it and re-whitens it appropriately.
Grout whitener is really easy to use and generally will dry in less than 12 hours. You can clean up the whitener if it is spilled with a simple warm water solution. Grout whitener will last a long time. You do not need to worry about your animals around the fresh whitener because it is non toxic.
Decalcifying Gel
Decalcifying gel is used on your tiles, like the grout whitener. This product can also be purchased at any local home improvement store. Use this product when you are looking to remove lime and mildew build-up in and around your grouted areas.
Source: www.DoItYourself.com