I have the artic butterfly and you would need to be VERY rough to scratch
anything with it, I second the grease suggestion, I did that first time using it
there is an area around the sensor that has grease apparently to catch the
dust when the self cleaning action is operated, a quick wet clean sorted it.
I thought I had scratched my sensor once, but when the initial sick feeling wore off, I looked again and realised it was a smear of grease. I gave it about 20 cleanings with the Arctic Butterfly and eventually it cleaned up OK. There’s grease around the inside of your camera and you can pick it up on the brush if you touch the sides when cleaning.
Alex.