For the first year of owning my neoprene covers, I used a product by Blue Coral. It was called Dri-Clean, in a blue can. It's like dry cleaning. you spray it on, let it foam, then scrub it with a dry brush and viola, the stains came out. But after a year, I threw mine in the washer twice. They came out good, but one of the back cover's seams unraveled. I had to take it to a upholstery guy to re-sew the seam (since neoprene doesn't fit in a regular sewing machine!).