Usually you can get them off with just some rubber grips, but with super-stuck rangefinder and viewfinder surrounds, there is the Right Way or the Wrong Way to get them to move.
The Right Way is to use a correctly sized ring wrench - something like
this one NobbySparrow sells on eBay. They should grip the little buggers perfectly and let you remove them without mauling them to death.
The Wrong Way is to use a pair of pliers, grip the thing as hard as you can, and turn. This will, obviously, absolutely batter the hell out of the camera, but it'll let you get into it.
...
however, there is a middle ground. If you are very,
very careful, you can wrap a couple of layers of duct tape around each jaw of your pliers and pad them enough to not leave any visible marks on the camera. This is - needless to say - very,
very dumb, but it does work. You just have to take it very slowly, ensure you don't let the damn things slip off, and repeatedly check you've not cut through the duct tape.
I literally just did that this afternoon to remove the rangefinder surrounds on a rusty and neglected Moskva 5. It does work, but I begrudge recommending it to anyone as it is very easy to permanently damage something. Last resort only - and definitely not something to do on a super-expensive camera.
