how clean do you want it, and where do you want it the cleanest?

for a few bucks at walmart get a swiss army knife, "the smokers tool chest", and use the scraper that comes in the normal sized ones, not the tiny ones to scrape the bowl out as best as possible and get the mouthpiece as clean as you can.

or you could take some alcohol and just run it through the bowl end so it only runs through the places where the smoke passes, this could be achieved with aquarium pumps and the such so that you dont soak the bowl in alcohol which could ruin the finish.