Don't forget to clean the ring grooves and the rings of the piston.
I'm talking about removing the rings from the piston and doing this.
stem of a cotton swab or a toothpick pushed tight into the ring grooves and go all the way around the piston.
Rings get wrapped in a soft rag and worked around a circle in your fingers.
Lastly, take something soft like toilet paper and kind of stuff it into the ring grooves and feel for anything rough.
Also do the ring wipe again, with the TP
You're looking for anything that snags or hangs or feels rough.
Could be embedded debris if you feel something drag or snag.
Also helps you look for a burr or chipped spot on a part.
The paper should be pretty much clean after the wipe, and the grooves and rings dry.
IF you're leaving oil behind still, then you're not completely wiping the parts clean.
Assuming you've gotten all of the contaminants, fleck of plating, aluminum or anything else, out of the grooves and off of the rings.