I scrub with tooth brushes, use plastic polish to shine up lens and file contacts and sockets after breaking corroded bulbs free. The damage was so bad to the passenger turn signal that I rebuilt the back of it with J-B Weld. Then, the entire assemblies get two coats of “chrome” Rust-Oleum paint to protect what little pot metal was left but also to add some reflective shine to the unit. I looked into replacing some bulbs with LED lights but decided against it for a few reasons. One, the cost. No sense in spending more money than I have to on this car. Two, the low wattage tricks the relay into thinking the bulb is burned out. The solution is to wire in a new relay so the turn signal doesn’t go blink-blink-blink-I’m coming at you like a spider monkey-blink-blink-blink. But instead maintains a slow and steady blink… I’m turning now… blink… so nice to share this roadway with you… blink… enjoy your day… blink. Finally, the old Edisons are actually quite bright when everything is cleaned. Going from a car with one rear bulb working to turn signals, brake, reverse, interiors and all running lights is quite rewarding. It’s a little piece of Xmas lit up in the garage at night. Now to fix the headlights.