Sarah's idea of varnish would probably help a lot. I was going to suggest clear nail polish followed by sanding, but varnish would probably be better!! that would prevent some of the staining and the sanding should smooth them out.
but if you can be without the needles for a while sending them back might be best. (they will probably just ship new tips. cheaper for them than rehabbing.)
did I say one project at a time?