Any corosion on the plunger of the solenoid should be removed. As a tool for it you could use a Dremmel or Proxxon with a blue polishing wheel.
No grease or lubricant should be applied.
For the "curtains" : take pic's ! Digi, if you have, is the easiest.
Degrease all the moving parts of it with Q-tips and some solvent: lighter fluid, petroleum or what ever.
DO NOT USE ACETONE as it desolves the plastic.
You realy have to clean that section thoroughly, hairs and dust can be removed with a small brush and a vacumcleaner.
Try if it works without grease first, if it does not run smoothly than apply a very thin coat of lithium based grease with a Q-tip or brush.
The curtains can be reached by removing the top (as if you have to replace the lamp) but having the bottom off gives you extra access to them.