There are several ways to restore your grout and tile in your shower to its original condition. One way is to use a power washer. This will remove any particles or grime that has built up in the grout's surface. Another option would be to use a tile and grout cleaner. This will help to break down any stains that have set in. Then, you can use a grout sealer. It will protect the grout from future stains and damage. By taking these steps, you can ensure that the shower tiles and grout remain in good condition for years to come.