Put on a face mask and rubber gloves to avoid inhaling or directly contacting the mold and mildew. It it's a large buildup of black mold or if you have respiratory problems, you should use a respirator mask.
Mix 1 cup vinegar with 2/3 cup water in a spray bottle. If you have a larger area that you need to clean, just increase the amounts of vinegar and water equally.
Spray the mixture directly on the mold or mildew and allow it to sit for 30 minutes. After 30 minutes, spray a little bit more, then scrub gently with the sponge. At this point you should notice that the mold and mildew are coming off.
Spray the area again with the mixture and wait another 30 minutes if there is some remaining mold or mildew. This time wipe away the remaining fungi with a clean rag.
Rinse with a clean damp rag and dry with a towel.