Quote Originally Posted by E. von Hoegh View Post
A piece of sheetmetal ground/filed to clear the glass and fit into the spanner notches is a far better solution. I'll forgo taking something apart rather than use the pliers approach, it's no substitute for a spanner and a very good way to ruin both the pliers and whatever you are trying to take apart.
The method used in a factory is a special pipe tool with two pins ground or inset to fit the ring notches and a handle at other end. Much less likely to slip when the piece is an inner ring as the pipe is sized to be constrained by the side walls. Similarly on an outer ring the pipe is just sized to clear the ring internally.
A spanner wrench is a poor substitute.
Not damaged anything yet with pliers.