Vermeil is a coating of gold over sterling silver. It's an inexpensive alternative for having beautiful jewelry at a mere fraction of the cost. Produced by electrolysis or by fire gilding, this style of coating precious metals can be dated back to the 1700's in France where it was actually banned because fire gilding was causing blindness due to mercury levels. Electrolysis is the common method currently used; it is the safer alternative.
Mix baking soda and water in equal parts into a paste. Mix enough to cover the vermeil item. Start off with a 1/4 cup baking soda and 1/4 cup of water and mix more as needed. Chemical abrasives are too harsh for vermeil such as soaps and should be avoided as this can cause a chemical reaction and discolor the jewelry.
Apply the mixture to the vermeil by gently caking it onto the item with a nonabrasive clean cloth. Vermeil is made of gold so it scratches easily. Avoid using any cloth or material that may be abrasive.
Rinse the paste away by running the vermeil item under warm running water and wiping it gently with a soft clean cloth. Never rub in a circular motion as this may cause scratches. Up and down in the safest way to clean gold.
Dry the vermeil with a soft dry clean cloth. Buff it to bring back the shine.
It is recommended to keep small vermeil items in airtight bags, even though the gold may not oxidize the sterling silver underneath will. Some recommend that even using baking soda paste may be too harsh for vermeil. The best way to clean vermeil is to polish it gently with a polishing cloth and store in an airtight bag.
Avoid the use of harsh chemicals and abrasives.