A gallon pickle jar loaded with about an inch of Copperhead BBs* and filled with a quart of parts cleaner is a great way to clean up nuts and bolts you plan to reuse.
Just dump all of the nuts and bolts in, shake that thing and enjoy working with clean fasteners. This will also get all of the dirt and grease out of the way so you can see if the threads are in good shape or if they were butchered at some point in time.
*I use the copperhead BBs because I suspect they are easier on the threads. I don't know if this is true or not.
