After machining on a block or as in this case,I would take out the
oil galley plugs and put the block in the back of your truck and go to the car wash with it.......I wash everything with the high pressure hot water, especially the
oil galleys to get any debris from the machining out or as in this case any debris that could have been floating around the block.....then when I get home, I blow dry it with compressed air to get all the moisture out and spray it with WD 40 or something similar to prevent rust till I put it back together....
David