I’ve done the same thing @SpecialEd, somewhat messy, true, but didn’t lose much oil to speak of with the finger in the hole “quick-change” technique you describe.
When I heard the puzzler, that wasn’t what I was thinking the guy was doing. I thought he had dropped some small but critical part into the recesses of the engine, couldn’t find it, and was using the vacuum to try to retrieve it.
I’ve used a shop vac for this purpose, not just for cars but for finding any small part you’ve dropped and can’t find – and it really works well. Just put a nylon sock over the end of the vacuum hose, hold it on w/a rubber band. Then turn the vacuum on, and vacuum up everywhere you think the small part might have bounced to. It won’t go into the vacuum, everything will stick on the nylon sock surface, held there by the force of the shop-vac vacuum. Then you can simply sort through everything stuck there on the sock to find the part you are looking for.
This really came in handy one time when I was repairing my mechanical cuckoo clock. You know, the kind where you have to pull up the weights every day to make it go. The mechanism’s clutch (the part that allows you to change the time manually by just turning the minute hand) is held on with a tiny pin-like thing, like what you’d have if you cut the very tip 1/4 inch from one of those pins that come-with when you buy a dress shirt. To meet it’s purpose, it’s made of stainless steel and of a very stiff, springy type of steel. I dropped that thing, and I could hear it bounce around, seemingly all around the room after it dropped. But I couldn’t find that tiny thing no matter how hard I looked, even after 30 or 40 minutes of looking. So I got the shop vac out, with the afore-mentioned nylon sock, vacuumed here and there, and had found that tiny steel pin within 5 minutes.