Making Soft Copper Washers

[NortonDommi]

"Dumping copper in water after heating to dull red is not necessary, if left to air cool it will suffice." True but dropping into cold water has two benefits. 1: It cools down fast ready for immediate use. 2: Most of the Oxides slough off leaving a clean surface.
If you wanted to make real nice you could soak in White vinegar for a while to brighten.