This is the more advanced shutter of the pack film cameras. It has a film speed selection dial, as well as a scene selector which gives you a multitude of exposure settings.
Whatever model you have, they all come apart the same. Remove the 3 screws. Notice the one by the shutter release cable is longer than the others. The front should now come free completely, leaving the circuits behind.
With access to both sides of the front lens, clean the element thoroughly. Don't neglect the electric eye lens either.
When you turn the exposure control ring around the front lens, it moves a tinted piece of plastic up and down in front of the electric eye, blue arrow.
Move the piece all the way down so you can clean the back of the electric eye lens.
This shutter had a small metal spacer inside, red arrow, make sure you remember where it goes and don't lose it.
If the inside of your circuits are really dirty, you may have to really clean them, check electrical contacts and movements of all parts. Luckily this one was really clean, so its only a quick once over of all the moving parts and keeping an eye out for anything odd looking.
The circuits are in two pieces, one for the electric eye, blue arrows. The other for the shutter, red arrows. Once removed you can flip the circuits out and clean the other side of the rear lens element.
Put everything back together the way you found it.