"Ran when pulled"

Doesn't look all that bad from here, probably WAS running fine when pulled
I haven't torn down a lot of older engines before, and this one cylinder is different than anything I have seen before. I know it's been sitting for awhile but it seems like a lot of scaling in that one cylinder and I am not sure why it's just that one, nothing unusual on the head and the gasket was intact.

Are there any tricks to cleaning up the cylinders/pistons without damaging the rings or the cylinder walls ?