The copper beads (bottom) have oxidized quite a bit. The bronze beads on left have oxidized slightly more than the bronze beads on right. I applied Renaissance Wax to one side of the necklace, but it did not slow down the oxidation at all in this case. I don’t mind the look of oxidation on these beads. They also polished easily with a Sunshine™ cloth.
In selling jewelry with high polished copper clay components, I would let the customer know that the copper will oxidize more quickly than the silver or bronze. If they want to restore the bright copper finish, I would suggest using a polishing cloth, or include one with the sale of the piece.