If it mounts with a grommet, remove the grommet and mount it tight, if possible.

Fill the bell with a half sphere of foam rubber.

Stretch a rubber ring around the bell when the clapper hits it.

Install a resistor in series with the coil to weaken it.

I have no idea if any of this is practical or will even work. Let us know what ends up being the solution!

I put three strips of friction tape on mine and it seems to cut down the sound enough for me.

Curious here what really works. I haven't tried anything as of yet. Not sure if I want to just yet, or if at all. But, my bell is awfully loud too. Like it that way, but it will wake people up no matter where they are in the house. Keep us posted....

I glued a piece of thick leather on my GL, that took away the "edge" of the bell.