Are you talking about the little bat type one-hitters? Some even look like cigs? I don't know how you'd ever get a bud through one of those, the hole is just too small. I always get a wire clothes hanger (just about the right size to go through the one hitter) and cut it so I have a good straight piece. Heat up the wire with a lighter and push it through. You should have the resin built up at the end. Save the resin to smoke and then if you want the hitter sparkling clean soak it in alcohol like FunkeyMonkey said.