Once you have all four screws removed, you can take everything off the front of the camera and lay it out in preparation to giving each piece a good cleaning. These are the pieces you should have:

1. 2 shorter screws from the front of the camera.
2. 2 longer screws from the top of the camera.
3. The aluminium face plate.
4. The plastic lens shield.
5. The square glass plate protecting the internal lens from dust.
6. Viewfinder mirror.
7. Viewfinder top lens holder.
8. Viewfinder spacer.
9. Top viewfinder lens.
10. Front viewfinder lens.

Now, a couple things you'll need to remember for when you put everything back together. I almost always forget to put in the little square piece of glass before I put it back together, so don't forget it! The spacer in the viewfinder is curved and the open side of the curve points backwards with the arch-shaped opening pointing down. The top viewfinder lens is flanged differently on the top than on the bottom. Just remember that the smaller flange goes up, through the aluminium faceplate piece and the larger flange will fit down into the mirror assembly area. And when putting it all back together, the front viewfinder lens is flat on one side and curved on the other. The flat side goes backwards, toward the viewfinder assembly area and the curved side points forward.