You don't really wash any denim. If you jeans are starting to smell like balls, you probably should shower more, but some say you can roll them up and stick 'em in the freezer the kill off the odor causing bacteria. Some cats dry clean but these days if I MUST wash em, it's inside out in cold water and hang dry.
But really, this is why you've got to buy denim like hoes buy panties, if you have enough denim in rotation you aren't tripping off tossing a pair out when it comes time to wash them. Like it or not, once you wash them, they aren't coming out the same jeans you fell in love with.... unless they're just your run around jeans, then you probably won't care watching the dye running off into the sink from your washer during the wash cycle (My run off hose is attached to sink to the left of it)