Great news Fred! Now you know why I switched to using a Dremel... I gave up the hand polish after 10 minutes
There are dozens of polishing compounds available from woodworking places. Sticks, blocks, powders, creams... Various grades. Hard to know which is better for what purpose? I just used some stuff I had laying around...
But I never thought of 'Bon Ami'? Have to look into that... And maybe 'fix' that one nice lens I have that I can't use in direct sunlight?
I would be careful of 'pumice' though. It's just crushed volcanic rock after all and the general grades of it are about the same as an 80 grit sand paper that last time I saw it. Although it's a bit finer in 'Lava' soap bars I'm sure it comes in just about any grade as could be wanted if you could find it though?

I remember Bon-Ami from when it was the only window cleaner. Came powdered in a box, and its Motto ( Hasn't Scratched yet)never tried it on lens though. Russ