Steps. Use hot water with soap and baking soda to remove most of the mold. Mix a solution of part bleach to parts water. Spray the area with the bleach solution and allow it to dry. Spray a second time and scrub with a brush. Rinse and repeat as necessary until the mold is gone..Cleaning mould from your bathroom or wet room walls, tiles or grout is never an easy task, however large or small the room. Because of this .How to Remove Mold with Baking Soda. Mix cup baking soda with one gallon of water and spray the mixture on the affected area. Dip a damp sponge into pure baking soda and scrub down the tiles and grout with it..