Pieces of steel in cylinder??

I'm lazy; I slam it all together on the engine stand, turn it upside down, jam some paper towls into the exhaust ports,and then splash some paint on it. Then rotate it rightside up and finish it. Since the engine lift-plate is on, I mask nothing.
Your way is just extra work, and yur gonna get it all full of fingerprints,lol.
Either way is fine.