OK here is the explaination of why you use alcohol. Resin is an oil based substance. Therefore You have to use something that will break down an oil based substance. As most of you SHOULD know by now in your lives, water doesn't break down oil. What you are doing when you put it in Boiling water is you are making an oil and water suspension. What happens when you let the water cool off after you have boiled your pipe? I'll tell you in case you haven't let it settle. You have water with a layer of resin on top of the water. If you do the same thing with the alcohol you have a resin and alcohol solution. So all you are doing is spreading the resin around. I bet when you get done cleaning with water it has to be sticky as hell now you know why.Now I will be the first to admit that it will do a lot to clean your pipe. But if you want that son-of-a-bitch spotless like it is brand new the only way to do it is Alcohol. As I said before the salt doesnt really do much all it is, is an abrasive. But it does help with the really thin resin coating that gets all over everything.
Also I saw that Kochab you only clean your every four months? Man, I clean my bong every 2-3 weeks. My pipes I don't clean nearly as often but I don't use them nearly as much.