Every technician carried a "pink-pearl" eraser in his tool kit. Edge connectors, whether gold-plated or not, tend to accumulate dirt between the board-fingers and the backplane connector's contacts, and the eraser was a good tool for removing it. Unfortunately, the dirt works its way into the connection whether one takes pains to avoid it or not. Sooner or later, the contact becomes intermittent, unless one removes and cleans each board from time to time.

I can't count the number of erasers I used up doing the above, but that is not my worst recollection of "handling old stuff"

Once I spent Christmas and New years in Paris, France, supervising a couple of techies soldering resistor leads through EVERY 'plated' hole on, who knows how many, PCBs and replacing boards in several machines with fixed boards, testing the result and giving the removed boards to the techies for the next run of fixing.

Erik