New caps have arrived for restuffing
I also tried out some GoJo on the chassis. It does a fantastic job removing the baked on crud. The cleaned metal gives off a black residue though. As if it's immediately oxidizing on contact with air.
The gray on the paper towel is the dirt. The black below it is from wiping a few minutes later. The paper towel also leaves very fine scratches on the metal.
I've rub down the chassis with BoeShield T-9 once it's cleaned.