Who-o-o-a there, pardner! This one is a bit vicious. Scratches are deep, and metal is removed (not "moved") real fast!

Those bristle ends are as nasty as they look.

As can be seen from the above photo, I whizzed the coin in halves. I used this brush on the LHS, then stopped and had a good look. It didn't look too bad, naked eye. However, my eyes aren't what they used to be (they used to be my kidneys), so I used the loupe. Whoa! The whole left side had a frosty sheen that was most uncharacteristic!

The scratches didn't look too bad until I put it under the 'scope. Bummer big time!

I tried a little more with this brush, applying as little pressure as possible, but the result was inevitably "Grand-Canyon"-style scratches.

I wonder if I could glue those filings back on...