I recently bought a magnesium Calumet C1 from a fellow apug member what was complete (well, except for a bunch of broken plastic knobs), but very corroded. It needed to be completely disassembled, all plastic knobs replaced, sanded, masked, repainted, and reassembled. I documented the teardown with my digital camera (a great use for one of those things) and posted the images on flickr in my account (name is fotofish) if you are curious or need to see how to fix yours. The knobs were the hardest part because they are very non-standard. I ended up modifying and/or disassembling some off the shelf knobs from Reid Tool. If you want details, let me know. I refinished the parts with Rust-o-leum green hammertone paint. The hammertone seemed appropriate to the period and hid a lot of surface defects. Highly recommended! In the end, the camera works pretty much like new. I'm not sure whether I'll end up keeping it as it is a beast even in magnesium, but it was a great project that turned out well.