Another technique I've seen to give a candy-coat appearance is the use of glass paints over polished metal. Pebeo makes a glass paint called Vitrail that can be purchased here.
2 Roses Studios have developed their own method of adding color to metal. They told me once it involved colored pencils...beyond that, it's a mystery to me, but shows with some innovation and tenacity what can be achieved.
How do you make your work more colorful?