Originally Posted by Chasing Hawk
Vinegar also cleans rusty bolts and nuts.
Put the offending fasteners in a bucket and cover with vinegar. Let sit a day or two, then thoroughly wash the nuts and bolts. Use a wire brush if needed to remove any stubborn debris. Make sure that you use plenty of water to rinse because the vinegar will continue to eat away at the metal. After they are dry spray with some WD-40.
I have also used it to remove rust. as in above quote, works really well to clean up rusty horse shoes.
I also use as a general cleaning product with bi-carb. :-D