Not recommended for the faint of heart, but our son has been known to scrub it with a Scotchbrite and then spray it with brake cleaner. Clears it right up. He says you may want to strip down or wear a Depends during treatment. 

Alternative treatment: OTC stuff called Zanfel. NOT cheap, but works well if early in the breakout. I've heard that HyVee pharmacy has a generic OTC like Zanfel for about $5 or so. Can't speak to that from experience.