Plasma annealing is not only a highly effective but also efficient method of cleaning wires, strips and tubes.
I personally have (witnessed)copper and copper alloys with great success at the plant in Austria.
For example, running a SiBz 1.7 mm wire we were able to not only run fully annealed but also anything in between, resulted in a remaining oxide layer of only 120 Angstrom.
I need to point out that plasma annealing is not a substitute for resistance annealing. If resistance annealing is getting you basically the results you are looking for it will be a more economical process.
Feel free to contact me for more detailed information.