Restore the finish of tools

I have some tools (wrenches) that have lost their finish. What is the process of getting them as new? What is the proper finish to them?

Thanks

RIchard

Clear Zinc Plating works great.

I am not sure the exact original finish. Porsche used Cadmium mostly. Could be either cadmium or zinc. Zinc lasts longer and is brighter, less toxic. Seems like there are layers of the stuff on the tools, as you glass bead blast a tool the skin layer peels off.