Cleaning the engine innerds

[Subzilla]

I'm prepping the block to throw the heads back on. Had some gasket debris and other sanding "stuff" in the cylinders sitting on top of the piston so I vacuumed each cylinder last night. I was wondering about any micro grit that stuck itself to the cylinder walls or might be nestled down at the piston rings. Any good way to ensure I have it all out? And should I recoat the piston walls with 15W40 or some other suitable lubricant? Guess I'm a little nervous about scoring the cylinder walls.

I stuffed rags into the upper openings of the block but I know stuff fell in the bolt holes when sanding/scraping. Should I be concerned about this?

[NH2112]

I'd just give each cylinder a good blast with compressed air, and make sure to check the coolant passages for debris too. As far as lubing the cylinder walls, maybe a coat of 15W40 or assembly lube, followed by rotating the engine to give everything a light coat then wiping off the excess - you don't want it getting squished on the compression stroke. Or, you can use a drill with a cheap 1/4" drive extension & 5/16" socket to prime the system before cranking.