FB, I wouldn't use salt. A bucket of salty water to drop them into, yes, but the salt will not do your plants any good at all. If you get a slug and cover it in salt, it's like some disgusting effect from a sci-fi movie. I didn't know about that until I moved into a shared house at college which had a serious slug infestation, not helped by one of the girls leaving food out all over the place, we had a serious clear-out one day, and found an apple crumble absolutely heaving with the things. She accused us of eating it! Next time we just left it out, and let her clear it up!!
FG, the bitumen paint is very good on rasied beds, but is black like tar, so if you've a veg patch covered in brand new beds, it might not be the way to go! It does dry quite quickly, so as long as you're careful, I don't think it will be an issue with plants, especially if you do it on a dry, still day (I know we don't get many of those). It's great for beds on an allotment, though, where looks aren't that important.
