I have the opportunity to buy a used custom knife. Its carbon steel and the blade shows a lot of discoloration. More than just the grey patina, but lots of golds and blues. I have just seen pics but am concerned that its been in a heat source and the temper is gone. But do remember having a Western knife years and years ago that discolored the same whey when I used it to cut pizza and left the knife dirty overnight. Do you guys think these golds and blues should stop me from buying the knife. It is very very expensive. Help Jack