I had my Canso emblems redone, cost lots of $$$. Try Dale's Muscle Car Parts, he did some repops of the Canso emblems for 66&67's and they look very excellent and the price is better than redoing them.

pictures /year of car works great (I may be able to help you better)

Emblem restoration is a time consuming endevour for sure.  The first thing you have to do is find out what metal it really is.  A lot of people believe that POT METAL was the choice for GM.  They only use that when they had nothing else, their choice was white metal.  The easiest way to repair  pits is to tske s drill bit and gentle remove the pit then fill it with Silver epoxy, sand it smooth with 2000 grit paper and poish it with a leather strop.  Now it can be sent to a rechromer.  The other way I have done this is to drill a hole right through the piece the same diameter of a copper wire then silver solder it on both sides. Sand & polish then send it out.  If you dont get a good finish on it before sending it out then it willl come back looking like crap.  Remember, Garbage in garbage out.    I will post a complete procedure a little later with pictures.  Good Luck