One benefit that copper wires have is that these wires are made of copper and by default copper does not rust just like in the case of bronze. Copper has a little iron too. Although oxidation might occur at the surface forming a green film on the surface of the wires, it does not have any effect on their functionalities over time. The property of copper not rusting and where it is resistant to corrosion as well are some of the most important factors that enable one to choose flexible copper wires for several applications.