Star Brite MSR Black Stain Remover Mildew Stain Remover 

The special buffered formula will not harm vinyl upholstery or threads. It is a much safer alternative to using bleach, and can also be used around the home or in RVs wherever mildew stains are a problem.
Removes mildew stains on contact without heavy scrubbing, simple to use; spray on, scrub lightly and rinse off stains, safe for use on fiberglass, painted surfaces, rubber, plastic and vinyl headliners, bolsters and upholstery, special buffered formula will not harm vinyl upholstery or thread, ideal for home or RV use, too, does not weaken fabric or thread, formulated specifically for use on marine upholstery; will not harm vinyl or stitching.