If the plating is in really bad shape sand it off and polish the steel. It's a slightly different color than nickel but it will still shine well. I have buffing wheels on an old grinding arbor that I use. Start by sanding with a coarser grit sandpaper and sanding block, say around 200 grit if really bad, and work through the grits to at least 600 or so until you have a smooth flat surface. Now you can start buffing with a coarse buffing compound. Work from coarse to fine with your compounds until you get the shine you want. Use different buffers for each grit of compound and clean your work piece between compounds too. Caswell's has a free tutorial on their site and sells everything you need for plating and polishing metal. I bought what is probably a lifetime supply of buffing wheels and compounds from them about 10 years ago.
Rodney