Cleaning Jewelry Setting?

I have a pair of gorgeous cubic zirconia earrings, costume jewelry they are, though. There is one band of "diamonds" across the centers of the earrings, and a few of the settings behind the stones are tarnished. If I pry out the stones, I won't be able to set them back in, and it would be too costly to have them done professionally for only costume jewelry. Does anyone know how to get the tarnish out without removing the stones from the earrings? They are goldtone.

By Jazzmin Flower from Alta Loma, CA