how to remove mildew stains from bathtub caulk
1 Use a scrub brush to brush along the surface of the caulking, moving from side to side. 2  Apply light pressure or it may damage the caulking. 3  Rinse completely with water and/or scrub the surface again with the soapy water used earlier to remove any bleach residue. 4  Dry the caulking with a soft towel.5  Repeat if necessary. Allow the bleach to sit on the caulking for 10-15 minutes. 2  During this time, the bleach will kill the mold spores and begin to whiten the discoloration. 3  Use a scrub brush to brush along the surface of the caulking, moving from side to side.