Metal is porous. If you baste alloy housings like valve covers, vacuum pump, alternator and power steering bracket in engine oil then wipe it clean in a week you will end up with deep clean lustre. Ever notice how the oiliest part of the valve cover under the breather tube is also the cleanest?

Oil em up then wipe em down after they marinate for a week, says me. They wont shine like chrome but you'll get a clean deep gray finish from aluminum alloy components. Works great against dry oxidation of aluminum too.

Another idea is squirting tranny fluid on rusty looking nuts'n bolts all over the car, suspension and steering gear and brake nipples, etc. I keep an oil can of the stuff in the engine compartment for this. Major problem with old cars is nuts'n bolts rusting frozen. None of the engine compartment bolts and nuts are rusty/dry on my car. All metal loves oil. Its probly the best 'finish' you can apply.

(edit: And the Vintage Forum never goes dead. Post a thread and it can kick around for at least a week, nothing wrong with that.