gdb
1
Oxidation on gold
Reasonably pure gold (18k & up) does not naturally tarnish from oxidation in the way that sterling silver does. However the problem can arise, particularly with cast items that often suffer from micro porosity. Items made traditionally by rolling and pulling to size and shape from ingot do not suffer from this.
The porosity over time can leach out acids and cleaning solutions from manufacturing that will cause tarnish, they also trap the skin oil, perspiration, deoderants etc. that often builds up on gold watches as we tend not to wear them while showering etc. and this will oxidise and stain.
It's best prevented by regular cleaning. Where a build up has occurred, a gentle rub with warm soapy water on an old toothbrush will usually be enough to remove it. If more stubborn, have your jeweller/goldsmith polish it to prevent marking the surface finish.
Try Anti-Tarnish Strips by 3M...
