There are steps in the manual to remove the Upper PF. It's actually not as bad as it seems and the steps are laid out pretty well. Give it a shot.

I think you need to remove the upper playfield to deal with it unless you want to be very frustrated. There are instructions on how to remove the upper playfield in the manual. It's kind of a pain actually. I'd say about 1-2 hours of work to remove it and put it back. It will make working on that flipper 50 times easier though. Might as well clean and wax the lower playfield while you've got the upper off.

I just fully shopped mine not too long ago. Access to the bottom of the upper playfield is a PITA no matter how you slice it.

Removing the upper pf requires you to remove basically all the ramps in the game, and you'll have to disconnect all the connectors as well.

The fliipper mech can be rebuilt without having to remove the upper playfield. Good lighting and magnetic sockets are the key.

If lamp socket wires are in the way just remove the sockets and push the wires and sockets out of the way until your done.

Way above my paygrade...my upper flipper could use some fresh rubber, but looks like it's gonna stay.