Looking back at the topic of this thread it's occured to me that probably the most important practice to observe with plugs/physical connections is to make sure that both the male and female parts are the same base material if possible. Brass to brass, copper to copper, silver to silver is going to be better electro-chemically than mixing things up. A Silver to brass link woud be electrically ok but has the potential to cause a situation where the zinc [in the brass] decays by a displacement reaction with the silver.
There's going to be different techniques for cleaning plated connectors as against solid unplated material. A gold plated surface in good condition shouldn't need much more than a wipe with something damp to clean it and will be damaged by abrasive cleaning that removes plating. A solid copper or sliver connector, unplated, can even be cleaned with steel wool if needed.
jules
