Returning to PS

My right arm isn't what it once was, going back to PS. The reservoir was leaking pretty bad before and the way the outside of it was beat up I can see why. Anyway I cleaned it up and smoothed out the metal on the lip. My concern is should the inside be painted? I think not, but I'm not sure. However it looked like it was, but it all came off with the Simple Green, didn't on the outside though!

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