^Ruddy Americans, always wanting to shoot someone. Lol, just kidding

Don't bother with the violence, and just learn the lesson. You also gotta tink that the person you bought the weed from would have rather it didn't contain 'grit' aswell.
Find your self a propper dealer, not just a friend of a friend and all that shit, buy in sizeable amounts (half Oz?) to get alittle discount, and just store it. This way you don't have to deal so much, and have weed when you want it.