A long coat of mail reaching below the knees; the most important piece of protection worn defensively. In the 11c a hauberk might be worth about 30s. These coats were obviously subject to rust. The solution was a kind of varnish which gave the metal a yellow tinge, known as hauberc saffre. When the varnish had been removed through use and battle, the coat was abraded with sand, after which another coat was applied. Colour could be added to the varnish as the owner wished. -
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.