I hold some ancient dishes that stain from sitting, how can i remove the stain? They are trimmed in gold ingots and i don't want ruin it....

They are trimmed in gold ingots and i don't want ruin it. So please if anyone has a cheap just what the doctor ordered please let me know. Thank You
Answers:    Bleach soak it for 5 min. later wash I hold 18 k dishes and I do this
Some vinegar in the dish wash soap, does wonders! Good Luck!