Brown vinagar is twice the strength of white. Keep that in mind. Plus, the BB trick works best, if you fill a quarter full, seal the tank, wrap in a thick blanket and tape real good, fill our dryer with towels, and stick the tank in the blanket in the center of the towels, and fill with more towels. So the tank is close to center of the dryer basket. Turn on(with no heat if you have that option) and about a hour later, pull the tank, and empty the bb/s and the garbage. You may have to do this a couple of times, but it really shines the inside of the tank, and no damage to the paint. As far as CLR goes, there is another brand, called The Works, that you can get at any dollar store, for a buck, and it is much more potent than CLR. Requires gloves to use, and it eats rust like Pacman.