Having the "pros" redo an instrument cluster is a great idea, but if you are bucks down (as are a lot of us at the moment), or prefer to do everything yourself, just on principle, there is much you can do.
Pulling the gauges apart and cleaning the lenses will go a long way toward brightening things up. The first step after getting the lenses free is to determine if just cleaning will suffice, or if they need more, like polishing out scratches, or even sanding them. When sanding the heavier scratches out is needed, wet sand them, starting with the lightest grade sandpaper that will give you a uniform dullness, working your way to the lightest grade available to you. I start with 600 grit and see if it does the job of eliminating the biggest of scratches, if it does I move progressively to the smallest size grit, skipping a couple of grit sizes each time I change sizes (600, 800, 1000, 1500, 2000 is my usual progression). If it doesn't, keep moving up to the next coarser grit until you find the one that works, then start down the progression. Using the lightest pressure that still cuts, and keeping lots of lubricant flowing is key (I use dish soap and water). At that point I switch to plastic polishing compounds (hardware store, auto parts store, commercial refinishing supply house, mail order speciality house, it really doesn't seem to matter).
Often times if they are still sealed to their bezels and lenses, and haven't been exposed to the elements, you'll find gauge faces in relatively good or even fine shape. Those same gauge faces can be problematical if they are heavily stained, soiled, or scratched, and may require repainting and silkscreening by a pro, depending on your skill level. With the availability of dry transfers with different sizes and fonts, computer use friendly decal paper and programs containing virtually an unlimited number and type of fonts, this is far less a problem than it use to be. It also makes substituting movements something else you can easily do yourself, the substitution of a volt meter for an amp meter a prime example. Installing a quartz clock movement for the analog one would be even easier, by virtue of not needing face modification.
Normal body working techniques and materials can be used on the bezels if needed. There are cheap plastic welders out now (on sale at Harbor Freight among others from time to time) to enable reattaching mounting tabs, welding up cracks, and other misc repairs. Don't forget the various epoxies that can be used also. Repainting bezels with the appropriate colour and gloss paint, with a detail gun or an air brush, is also within the realm of doable. Pay attention to what special techniques might needed for those parts in need of replating and figure out if you can handle it yourself, or if you need the help of a pro. If there are extensive areas on your bezels in need of replating (often times, entire plastic pieces are plated, then selectively painted by the factory), perhaps sending them out to the appropriate vender would be best. But if you are careful, good results can be obtained on small areas with metalizing paint, leafing papers, or chrome tape.
It's your money and your time. Figuring out how to spend it to get the most bang for the buck is the trick.
