I would open all the screws to get any moisture and other crap that's gotten in to the threads, out of there and from the holes. Otherwise it might start to rust over time and can cause some serious problems.
Especially when it's that dirty
About those caps... well good quality capacitors are expensive as hell. Only one I'd recommend for something like this would be
genuine Nichicon's, and oh boy, are they expensive.
But you decide for yourself of course
