Several years ago I did wrote a few topics about Gold color painted banana plugs, audio connectors and test leads.
These sold a Gold plated.
Today I came across of a YouTube video, this man were cheated by buying copper color painted alligator clip.
Fakes detection method, this is always the same.
Heat the up them to 200 Celsius and then scratch their surface.
At the category of copper alligator clip or at the larger Car battery clip, there is not such thing as copper plated, both they should be made by pure copper, if this is of what you have paid for.