@33MHz CDC and EPA have good guidelines. Depends on degree but fundamentally soap and water, maybe bleach solution if more than a light amount. The key is to dry up after cleaning ASAP. Put some fans on that sucker.
@jws I've heard 10/1 water+white vinegar. Bleach yep. I'm figuring I'll put a few fans down there and rent a commercial dehumidifier for a couple weeks.