Well, I'm glad my search for "cleaning critical focuser" didn't bring up that post, or I never would have tried it today!
Luckily, like I thought, it was the rearmost "element" that was dirty. It's not really an element but just a piece of glass with a rectangle etched into it. I did as ic-racer describes and removed the 3 retaining screws (but next time I won't remove them, just loosen them a lot...if they fall and get lost they are tiny). The rear retaining assembly comes out of the shaft with a twist and pull; it doesn't screw in. The rear glass can then be removed from the inside of the retaining assembly with simple finger pressure on the inner retaining ring. I cleaned it up (it was nasty and foggy) and now it's like a brand new finder. I'm amazed that it got so junky in there. Thanks for the replies. If anyone needs to clean just the bottom glass from the inside out it's very easy. Just look to see what side the rectangle etching is on before removing that glass and put it back like it came out (I can't remember right now).