Best gunk remover is a colonic, particularly at a place where they know what they're doing (and use teas, aloe vera, essential oils, coffee, etc. I know that sounds obvious, but you wouldn't believe the places I've seen. You have to ask around in your area to discover who is best.
If you can't do this, do enemas -- help your body clear itself. There's so much gunk there it's very hard for your body to do it all on its own.