[xchcui]

Hi.

There are some mechanical ways to do that,but i am interesting
with the chemical way,which should be easier.
What chemical can i use to clean(remove)carbonized metal connectors etc.
which turned black due to repeated electric arcs?

Thanks.

[Enthalpy]

The contact are of copper alloy like brass I suppose? Being black suggests they use the wrong material for repeated unplugging. A gold layer would be better, or some hard precious metal.

If the contacts are well accessible, I clearly prefer mechanical cleaning. (1) Eraser if possible, it's the most caring method (2) The scratching back of a sponge, works often (3) Fine sand paper. I haven't tried scouring powder up to now.

If not, you might try iron perchloride FeCl₃. It tends to work faster than HCl. Rinse well any etchant, as it builds leak paths for electricity, and some electronic circuits are extremely sensitive to them.

I didn't try rosin and heat in this use, but this serves to deoxidize copper alloys when soldering.

Aluminium foil in hot (100°C) sodium bicarbonate or hot soda deoxidizes silver nicely. I didn't try on copper alloys.

[xchcui]

Thanks  Enthalpy.