Self-threading needles discolored
 

I treated myself to some self-threading needles for hand sewing. They are the kind where the thread slips in from the side, not the end. They are ridiculously expensive for a package of 8, 4 large and 4 smaller. When I took them out to use one last night I saw that the smaller ones had all oxidized and discolored. The larger ones are fine. I'm hoping they do not leave marks on the fabric (like rust would) or have a rough surface that could damage the fibers. Any one else come across this?

I have never had them come this way, but I've worn all the "shiny" off of them very quickly. I've not noticed anything coming off on fabric, but it does become difficult to use once the shine is gone.

Chances are they have simply discoloured and it will have no effect on their performance.