For the large area of dust on the inner surface of the chassis, it can be wiped with a dry wet cloth. The wet cloth should be dry as far as possible, and the water stains should be dried after wiping. Do not wipe all kinds of plugs, sockets, expansion slots and boards with water. The slots to be cleaned include various bus expansion slots, memory module slots, various driver interface plugs and sockets, etc. The dust in various slots is usually cleaned by oil painting pen first, and then blown out by balloon or electric hair dryer.
If there is oil stain on the metal pin in the slot, it can be removed with degreasing cotton ball dipped in the special cleaner for computer or absolute alcohol. When purchasing a special cleaner, one is to check its volatility; the other is to check its acidity and alkalinity with pH test paper. It is required to be neutral, and the acidic cleaner will corrode the board.
Cleaning the memory module and various adapter cards, including dust removal and cleaning the golden finger on the circuit board. The gold finger is the connection point between the circuit board and the slot. If there is dust, oil or oxidation, it will cause poor contact. A large number of failures in old computers result from this.
The gold finger of advanced circuit board is gold-plated and not easy to be oxidized. In order to reduce the cost, the gold finger of adapter card and memory module is not plated with gold, just a layer of copper foil, which will be oxidized after a long time. You can use an eraser to wipe the dust, oil or oxide layer on the surface of the golden finger. Do not use sandpaper to wipe the golden finger, otherwise it will damage the very thin coating.