Can I use Concrobium over an area that was previously treated with bleach?

When bleach attacks surface mold, it leaves a carbon layer residue that prevents Concrobium Mold Control from penetrating to the mold roots or hyphae. This can limit the product’s effectiveness. If you’ve already treated a moldy area with bleach in the past, you should first wipe the area down with warm water and detergent to remove the layer. Once the area is dry, apply Concrobium Mold Control as recommended in the usage instructions.