Well, it wasn't the case that every single link was immobilized by rust, but the two straight sections were pretty stiff and the whole thing was covered in rust. I had to use WD-40 and some pliers to get the straight parts to bend enough to get them through the little rollers in the derailer. Since a chain replacement is on my maintenance schedule for this spring anyway, I just took the whole thing off. I need the practice, since I am not Mr. Handyman.