Panel removal and disassembly was key (and a huge PITA) in this case. Galvanic corrosion had set in between the panel and hex fasteners so a few drops of PB Blaster were needed to break them free. The knob had to go too because the set screw was cross threaded so it and the pot were unsalvageable. Once removed, it soaked in warm de-mineralized water for a bit. It`s then wiped down along the “grain†with a Magic Eraser, a brilliant invention btw. Depending on the severity of the contamination, adding some dish soap or Simple Green to the process might be necessary but I wouldn't go with any thing stronger without running the risk of removing the silk screening. The Lexan meter window was removed and received the same treatment but was also polished with an automotive clearcoat scratch and swirl remover. Once clean of dirt, panel scratches were masked by a permanent marker and wiped down with 99% isopropyl alcohol which diluted and feathered the ink to only where it was needed. The handles and panel flat head bolts were sanded and painted with Krylon Satin Black.
If you find the fan noisy, just replace it. I added a second 300r/15W in series with the fan to the already factory installed resistor which further reduced noise.
But keep in mind that if you install the second resistor, your maximum fan speed will be were it`s presently at when the thermal switches engage.