Bronze wool / bronze wire brush / bronze wire brush on a Dremel / bronze wire brush on an electric drill. Most rust will come off with no chemical help.

However, if you want to help the process along, you can soak the small parts in vinegar. For bigger stuff, especially rims, I cut paper towels into long 3" strips, soak them in vinegar, wrap them around the part, and seal it in a trash bag for a couple of days. Most of the rust will then wipe off easily. It doesn't work quite as well as oxalic, but it works (and it doesn't present the toxic disposal problems that oxalic does).