Craig Phillips from Bathroom Mountain warns against using bleach as a quick fix for mold removal in porous materials like grout and caulking. He advocates for the use of three percent hydrogen peroxide, which is both effective against mold and gentler on bathroom surfaces. To tackle mold, Craig advises saturating the area with hydrogen peroxide for at least 10 minutes, with additional applications on vertical surfaces to maintain moisture. For thorough coverage, he recommends pressing cotton balls soaked in peroxide into moldy crevices. However, once mold has permeated caulking, complete removal is unlikely, requiring the replacement of the sealant. Craig stresses the importance of preventing mold by addressing moisture sources, such as using a squeegee and towel to remove water and improving ventilation with methods like extractor fans or open windows while showering.