Mix the baking soda and bleach together in the bowl until it forms a thick paste.
Apply the paste to the dirty grout lines. Be sure it covers the grout lines entirely; if it's too thin it will slide down the walls.
Let the paste sit for 15 minutes.
Work the paste into the grout lines with a scrub brush, paying careful attention to any discolored areas. (Don't scrub the paste away entirely–make sure the paste is still covering the grout lines after you scrub.)
Let the paste sit for at least another 15 minutes, or longer if your grout is really dirty.
Rinse the paste off of your tile and grout with clean water and a rag.
Remember that grout is always darker when it's wet. If your grout still looks dark and dirty after you rinse the paste away, wait until the grout is fully dry and it will look better!
Save your favorite projects!
Create a free account to easily save your favorite projects, tutorials, and recipes.