Got a pair of Minolta Hi-Matic rangefinders going thanks to my handy dandy gunsmith tools and soldering iron. The example below was the bigger challenge. Probably used once and stuffed in a closet for 35+ years. In the meantime, mercuric oxide escaped the surly bonds of the metal cell sometime in early 1980s and proceeded to munch everything in its path.
Dropped in some beefier 26 AWG wire for the ground. The original had 5 strands the width of a human hair--impossible to strip and reuse. Probably would have failed due to stress anyway, given the way + and - were all twisted and jammed together. Oiled up some of the visible springs and joints, and voila: