Michael Mueller has used another post production technique on his silver 3D prints to give them a little more character. See the before and after below.

If you want to try this for your own … if
you need some hints… … There are also a lot of
links in the web how to do this. All you need is a glass, water, salt, wire and a 12 volt dc power supply. 

Sounds like dangerous fun… For a slightly less electrically charged option you could try Mark Cheng’s methods.