Got a couple of Vtg Gs this week and I find the different wear-patterns very interesting. I've got a flairtip whose handle is practically mint but with noticeably dulled silodoors. I received a superspeed from a forum member the other day which has outstanding doors with a handle which needed a very good clean (to the extent that I'm leaving it less pristine than it probably could be so as not to cause undue wear) but was otherwise perfect. I'm assuming Nickel oxidises, but is there any way to tell the difference between oxidation and just the dust of age?