[chris vickery]

Brad, I hope I can help you on this.

I have refinished plates quite successfully using the following method. It is a little tedious and patience is required. The good side is that if you muck it up the first time, you can always try again.

To get the brass on black look, I first painted the plates with a satin black paint. Since the lettering is raised, all that is required is to sand off the high area.

If you get a very flat block of steel and cover it with some very fine grit emery cloth you can gently rub the plate, face down across the block to remove the paint. If done carefully your plate will look factory fresh when you are finished.
I work the plate in alternating directions to get it clean.

What this method really depends on though is how flat your plate is. If its warped, bent etc you will really have to work carefully.

As for your all brass plate, I'd go the brasso route or have it replated. You will probably find that it is actually brass plated copper. I have stripped them before down to the copper using a solution of muriatic acid. Beware though that it does strip all the brass and replating will be necessary.