Do not use those.
carbon is abrasive enough. No need to toss in aluminum oxide too.
with clean new razor blades it is extremely easy to push the carbon off the top of the piston towards the dish to keep crap out of the ring gap. A thin swipe of grease around the edge as it sticks up above the deck at tdc... will help keep it out.
then turn it down slowly towards bdc while wiping the grease and carbon off the bore.