What are people talking about when they say the metal has been annealed? Annealing is essentially a process where metal has been heated up to soften it. The more work hardened metal is (twisted, hammered, etc.) the more brittle it becomes. If you heat it up with a torch and then let it cool (or quench it in cool water) it will be malleable again. Metal will not retain its color if you heat it – when copper meets oxygen it begins to oxidize and turn black. That is why sterling silver turns black over time (there is about 7% copper in sterling). The metal must be polished or placed in a pickle solution to remove the oxidation.