From my Restoration Tips (gleaned from Rec.Games.Pinball)

(Bryan Kelly)
Newsgroups: rec.games.pinball
Subject: Re: cleaning the metal on machines

Here’s what I do Steve. Set the bar in the laundry tub and spray both sides with Bleche Wite. Let sit for a couple minutes then Scrub with a brush. Rinse thoroughly with water. Most of the crud should come right off. If not, repeat.

The top side of the bar should not be shiney. It should have a “grain” to it running length wise. You should be able to see this. Take 220 grit sandpaper and sand length wise. Basically, sand the whole thing going with the grain. I then take a 3M red sanding pad and finish it up. This is simply finer then the 220 grit paper. Not really necessary, but that’s just me. :-) Make sure you sand straight.

This same process can be done on the side rails and metal guides on the
playfield. It’s been covered here before.

I then put a coat of car wax on it and I’m done. :-)

Bryan (Goose Lurker, CARGPB14)