I've tried all the above methods except for molasses which I like on biscuits but it sounds too slow for cleaning parts. I also have an Eastwoood vibratory tumbler and it's great for hardware. It won't quite get the nuts and bolts as clean as bead blasting but it does fine for cleaning the parts when you are planning to reuse them or black oxide coat them. As far as replacing hardware rather than cleaning, I find that you can't get the exact hardware at the hardware store so I prefer to clean it are reuse it unless it's too rust pitted or stripped.
