I've harvested a lot of belts from the JY's over the years and have learned that it's impossible to remove rust stains completely. On dark colors, they can be cleaned so that they aren't quite as noticeable. Light saddle tan...never to my liking. That leaves replacement as your only real option. I once called Snake-Oyl in TX who is a well known seat belt restorer about 5 yrs ago. If memory serves, they quoted $135 per side just to replace the front retractable shoulder strap. That didn't include restoring the retractor assembly hardware if that's the source of your rust problem. If you can find someone who will sew seat belt fabric, you can do these yourself (contact me and I would gladly share the how to's). But, due to liability issues, I found that nobody in my area would touch it.