Pebble watch charging contacts worn out, options?
Id personally try rubbing the contacts with a tiny piece of 1000-2000grit sand paper to get some fresh metal exposed and periodically clean it with a q-tip dipped in rubbing alcohol.

Trying to apply solder is not a good idea because 
A: you don't know what material the pins are made of 
B: Too much heat on that pin will surely melt and distort the plastic case possibly ruining the contact area permanently