Some sterling silver I'm ok with and others I am not. 14K gold is usually ok though. Sometimes I'll wear surgical steel (i think?) thats meant for belly buttons or tongue piercings and those are fine too.

It's weird - my ears will burn with nickel and my stomach will get a rash if I wear a belt with a nickel buckle - yet I had nickel wires on my braces and no reaction whatsoever. The ortho knew I was allergic but tried them anyway and told me to call / come back if they bothered me and I never had an issue.