I don't have a Minolta but I had some kind of bug larvae show up in my Nikon FTn finder some time ago. Though it didn't interfere with the view or focus it bugged (pun intended) the heck out of me until I finally dug into it. I'm fairly mechanical mind you. Ended up buying a new (used) finder. IMHO unless the camera is unusable and you have step by step instructions leave it alone.