craftgrrl | New pendant necklace and question about metal allergies

Hey everyone, check out this necklace I made:

More on my blog

I wish I could say I made the pendant, but all I did was make the hemp cord and string the pendant on it as I went. I got the pendant from an artisan at an outdoor fair in Argentina a few years back when I studied abroad there. I made a braided hemp cord for it at first, but one of my knots came loose, and I've had the pendant just sitting around since then. I finally got some motivation to fix/remake it!

The question I have is about solutions for allergies to some metals. I've got "sensitive skin" that reacts to metal that has any nickel content, and possibly other metals but I know that's usually the culprit. This necklace gave me a rash after only two days of wearing it, and now it'll probably be a month before I can wear it again :( I'm curious if anyone has any good strategies for coating the metal surface so it won't affect my skin? I've always used clear nail polish in the past on things like belt buckles, but it always wears off pretty soon and as it does, it looks so ugly coming off. I'm not too familiar with types of sealers they might have at craft stores and whatnot, anyone have any suggestions for something that could coat metal permanently?