I used a fiberglass "Brush" for many years to clean corroded connectors, Like the 37 pin Centronics Printer cable from old school printers. The Brush I used was the one used for cleaning photographic film emulsion from Movie Film for splicing. They can be purchased in any camera store and are great for cleaning the green (nickle plating) crystals form poorly plated "Gold" connectors. They are however not real friendly to people unfamiliar with them as the tool WILL remove most anything if you scrub hard enough, a very light touch should be used and the tool is not usually required for plated copper but very good on unplated copper. Use with great caution.
Bob