My cousin who rides English ( I ride Western), her grandma gave her a blue nylon headstall, but she couldn't use it, so she gave it to me. I've been using it about once every week for lessons. My friend made me some blue nylon reins that matched the headstall in color. The reins have gotten kind of stiff at the bottom, and some spots have these dark marks that I think are from dirt. How can I clean these out well? How can I get out the dark spots and get rid of the stiffness? Thanks!