You've probably destroyed the old patina and it will take a long time for that to return (like years). Further rubbing is not going to add the patina back. There is likely some chemical treatment you can perform to add back a patina, but it would likely involve noxious chemicals and be best left to someone specializing in silver restoration. You also may have a hard time getting the two pieces to ever match again, although I suppose you could put the other one in the dishwasher and start from the same point with both.

thanks. we are resolved to leaving well enough alone. The dishwasher-treated dish has irregular spotting and cloudiness all over.