Grout Cleaner Paste

Steps

1. In a small bowl, combine 1/2 cup of baking soda with 1/4 cup of 3% hydrogen peroxide. Stir until it forms a thick, spreadable paste.
2. Add 1 teaspoon of liquid castile soap and stir again. The soap helps the paste cling to vertical grout lines and boosts its grease-cutting ability.
3. Apply the paste directly onto the grout lines using an old toothbrush or a small spatula. Press it into the grout so it makes full contact.
4. Let the paste sit for 15 to 20 minutes. For heavily stained grout, leave it for up to 30 minutes.
5. Scrub the grout lines with a stiff-bristled brush or old toothbrush, working in small sections.
6. Wipe the area clean with a damp cloth or sponge. Rinse the cloth frequently to avoid redepositing grime.
7. For stubborn stains, repeat the process on the affected areas.

Why It Works

Baking soda is a mild abrasive that physically scrubs away surface stains without scratching ceramic or porcelain tile. Hydrogen peroxide is an oxidizing agent that breaks the chemical bonds in organic stains like mildew, food residue, and soap scum, effectively bleaching them without chlorine. The castile soap acts as a surfactant, helping the paste penetrate into the porous surface of grout and lifting dirt so it can be wiped away. Together, these three ingredients tackle both surface grime and deep-set discoloration.

Alternative

• Replace hydrogen peroxide with lemon juice for a milder paste with a pleasant scent. Lemon juice is less effective on deep mildew stains but works well for routine maintenance cleaning.
• For extremely stubborn mold stains, make a paste with baking soda and undiluted white vinegar instead. Apply the baking soda first, spray vinegar on top, and scrub once the fizzing subsides.

Tips

• For floor grout, apply the paste and cover it with plastic wrap to keep it moist during the waiting period. Dried paste is harder to scrub away and less effective.
• Use a stiff grout brush rather than a toothbrush for large floor areas. It will save your hands and back significantly.
• After cleaning, consider sealing your grout with a silicone-based grout sealer. Clean grout absorbs sealant better, and sealed grout resists future staining.
• Store any leftover paste in a sealed jar for up to one week. The hydrogen peroxide loses potency once mixed, so do not keep it longer than that.
• This paste works best on white or light-colored grout. Hydrogen peroxide may lighten colored grout, so always test a hidden spot first.