Alright. You guys made me feel badly about my Liberty that sits on a stand and is my usual practice horn. Hadn't been cleaned in 2 years and was really looking tarnished. Decided to go the Aluminim foil route. Used both salt and baking soda and very hot water. After an hour it was improved but still needed a silver paste polish.
As I was working, several things occurred to me. When using silver polish, you do manage to get it on your hands and eventually on the female slide parts. That can't be good. Probably need to be more careful with the polish.
I ended up using Vasoline for the slides (and always put a little on the valve cap and bottom screw threads). As you insert the slide and work it in, occasionally a small blob ends up inside the tube. If .003 difference in bore can make a big deal to some, surely even an ever so small blob of slide grease in the tube should also make a difference, shouldn't it? Of course, you can always check to be sure there isn't any there by pulling the slide, but when you reinsert it, maybe it creates another blob. Sort of like how do you make sure the light goes off in the refrig when the door is closed. Ha.