How to Deep Clean Stubborn Grout Stains

Grout is the unsung hero of your shower, but it is also a magnet for soap scum, mold, and mineral deposits. Over time, that porous material acts like a sponge, soaking up everything that splashes onto it, which is why a surface wipe-down rarely cuts through the discoloration. Done well, restoring grout is less about brute force and more about letting chemistry do the heavy lifting before you introduce any physical abrasion. The secret to success is patience. If you rush the chemical dwell time, you will just be scrubbing the surface rather than pulling the grime out of the microscopic pits in the grout. Prepare to get your hands a little dirty, but take heart—once the grout is brightened, keeping it clean becomes a matter of weekly maintenance rather than a back-breaking project.

1. Remove All Moisture First. Wipe the shower walls and floor with a clean towel to remove all standing water. Moisture in the grout lines dilutes your cleaning agent, preventing it from penetrating the stains.
2. Activate the Chemistry. Combine baking soda and hydrogen peroxide in a small bowl until it reaches the consistency of cake frosting. Add a drop of dish soap to help cut through existing oils.
3. Pack the Lines Full. Spread the paste directly onto the grout lines using an old toothbrush or a grout applicator. Pack it into the lines generously so they are completely covered.
4. Let Chemistry Work. Let the paste sit on the grout for at least 30 to 45 minutes. The chemical reaction will lift the embedded grime and bleach out stubborn mold spots.
5. Scrub Until Grey Appears. Use a stiff-bristled grout brush to work the paste into the grout lines using firm, circular motions. You will see the paste turn grey as it pulls the dirt out.
6. Rinse and Buff Dry. Rinse the tiles thoroughly with clean water and a microfiber cloth to remove all residue. Dry the area again to inspect your work.