I often get asked about the proper way to clean enamel jewelry.  There are a few considerations to take into account;  Is your piece copper with enamel or is it silver enamel jewelry?  Is it vintage or a modern piece of jewelry?  Are there are gemstones set into the piece of enamel jewelry?  Also a few things to consider: Is the actual piece of jewelry tarnished or just the chain and bail.  So now that you have answered those questions to the best of your knowledge here are some ways to clean them accordingly.  

First off, if it is just the chain that needs cleaning and you can remove the enamel pendant from it then do so.  You can use a variety of ways to clean silver chains including: tin foil line a glass oven safe dish.  Put your piece onto the foil and pour 1 cup of boiling hot water over it (enough to cover the piece)  and add 1 tablespoon baking soda.  There will likely be some fizzing and bubbling which is the reaction that is cleaning the tarnish from silver.   You can also use dips purchases from a hardware store such as Tarnex on your CHAINS ONLY, although these are not recommended for repeated and regular use. 

If you need to clean your silver enamel piece and there are no soft gemstones (stones ranked a 6 or below on the MOHS scale) and they are not antique or vintage enamel jewelry pieces, then you can also use the tin foil and baking soda method mentioned above. 

For a copper enamel piece without soft gemstones, you can add white vinegar and salt together (about 1 cup vinegar to 1 tablespoon salt) and dip your piece in that.  This will quickly clean your copper back to a shiny clean finish.  Just don’t leave it in the solution for longer than necessary.

Another way to clean both copper and silver enamel jewelry with gemstones is with polishing cloths.  This can take some time, but it is safe and an easy "go to" after you've purchased a polishing cloth.  This way you can always do quick touch ups to pieces just before wearing them out without much ado. 

And let's not just forget that a little soap and water with a soft toothbrush to scrub your piece of copper or silver enamel jewelry will certainly make it look much better fairly quickly.  Enamel is glass so any everyday dirt, grime, and/or fingerprints will be washed away leaving the colors much cleaner and brighter.  Dawn is a degreaser as well and works rather well, but any soap can be used. 

But if your piece is antique or vintage or is just really sentimental or valuable to you, then I suggest contacting a local jeweler who works with enamel and have them professionally clean your piece.