White distilled vinegar, baking soda and hydrogen peroxide are all good safe and non-toxic natural cleaners that will remove mold. When cleaning mold yourself, always wear a respirator or a facemask that’s rated for black mold spore protection and cover your arms, legs and hands to avoid contact with the mold.
Pour undiluted, distilled white vinegar into a spray bottle and spray the vinegar directly onto the moldy area. Let it sit for an hour then wipe it off with clean with water. The black mold should lift right off. The vinegar aroma will dissipate in a couple of hours.
Another way to remove mold from walls is with baking soda. Add 2 teaspoons of baking soda to a spray bottle with 2 cups of water and shake well until dissolved. Spray it on the moldy area then clean the mold from the surface with a scrub brush, and rinse. Spray the area again but let the surface dry, this can kill left over mold and can keep mold away.
To kill mold with hydrogen peroxide pour a 3% hydrogen peroxide concentration into a spray bottle and completely saturate the moldy surface. Let it to sit for 15 minutes, then scrub the area to remove all of the mold. Wipe down the surface to remove residual mold and mold spores.
Here’s a good guide about mold from the EPA