Here is what I would do:
dis-assemble COMPLETELY
replace any cheap parts (springs,pins,grip screw inserts..etc)
Tig weld any pits to deep to polish out (1mm pit would take a long time to polish out!) or maybe JB Weld?
Sand and polish to about 1000 grit
paint with CONDUCTIVE silver paint ( caswellcanada.ca/shop/silvaspray-conductive-paint.html )
OR
conductive copper paint ( caswellcanada.ca/shop/copper-conductive-paint.html )
then I would powder coat it myself ( a kit on ebay WITH sample powders can be had for around $150 CAN delivered ) or have someone do it for around the same ballpark price.
I think that would more or less restore it in the least expensive way...
IMHO of course. I am no expert... just sorta handy
EDIT:
Copper is the way to go.. silver paint is very expensive