Enamel brooches are so very colourful especially vintage silver and enamel ones. Just take a look at the pictures in this blog post to see some of the variety available.
There are several different types of enameling but they seem to have one basic thing in common – they are a coloured glass applied to the silver. It seems that the glass is powdered and they applied to the base material before being fired at very high temperatures.
The base material is often silver but can also be ceramic or glass or other metals.

The different types of enameling seem in Vintage brooches include;
Engine turned enamel, cloisonne, champleve, plique-a jour enamel and hand painted enamels.

All of these types of enameling add to the desirability of any vintage brooch. It was particularly common in the Art Nouveau era and is one of the features of Scandinavian silver jewellery.

Some care needs to be taken with your vintage enamel brooches as the enamel can chip and crack. It is difficult to repair the enamel and the end result seldom matches the quality of the original work. I suggest that you never clean your silver and enamel brooches with silver dip. Just a gentle wipe over the enamel with a damp cloth should be sufficient for the enamel perhaps you could clean and silver areas with great care and a silver polishing cloth?