Caring for your costume jewellery
Store your jewellery in a cool, dry place, away from contact with makeup and toiletries. A silica pack could also be used to absorb any moisture from the surrounding environment. You want to keep your jewellery as dry as possible because moisture can fuel the growth of verdigris and corrosion.
It's best not to submerge your jewellery in water. Stones and crystals on vintage jewellery may have been glued in place using water soluble glue. The adhesion of the glue could be compromised with exposure to water.
A good method to brush away dust and dirt from your costume jewellery is to utilize a cotton bud or a soft toothbrush. These aren't too abrasive and so shouldn't damage the finish.
Stay away from silver polish!
Plating on costume jewellery can be very thin, so vigorous wiping or chemical polishing can rub away the finish, causing permanent damage.
what is verdigris?
Verdigris is that green moldy looking substance that you often see on vintage costume jewellery. It's frequently found near the clasps because this is often where the most moisture accumulates. Verdigris is actually an indication of corrosion to the copper or brass base metal of your jewellery.
Verdigris actually eats away at the metal in your jewellery and so should be removed if possible, as if left unchecked it can damage the finish more or spread to other pieces which are stored in close proximity. It can eventually cause brittleness to the metal, compromising the integrity of your piece.
How to remove verdigris
The first step should be to remove the verdigris 'crumbs' with a toothpick or cotton bud.
An acidic substance like vinegar, lemon juice, or even ketchup can be applied to the remaining green area, left for a few minutes, and rubbed away with a soft cloth or cotton bud. Rinse away with a damp cloth and dry thoroughly.
Be aware that the finish under the verdigris will likely be damaged.