Becoming a hero has always been largely a matter of vocabulary.
A tooled-up thug, or a knight in shining armour?
The head of a cult, or an inspiring source of wisdom?
A torturer of heretics, or a saint?
A scavenging stroke has a heroic ring to it - it sounds like the fatal claw-stab as a falcon stoops on a partridge - but a scavenging stroke is actually the final movement of the piston in a four-stroke engine.
No, it's all right, it's not complicated. An engine is basically a box with a plunger-type thing called a piston attached to it that sucks stuff into the box, or allows stuff out. The first pull of the piston sucks in the fuel (that's the first stroke of the four strokes) the first push of the piston squashes the fuel (the second stroke) so that when it explodes the fuel pushes the piston out again (third stroke) and the second push gets rid of the waste gases (the fourth stroke).
Then it all starts again.
All visitors to The Word Den are, naturally, notably intelligent, but unless your own intelligence is artificial you're unlikely to possess pistons.
Still, by analogy it seems reasonable to me to term the expulsion of waste gases a scavenging stroke...
...and thus make heroes of us all.
Thing To Do Today: a scavenging stroke. The word scavenge comes from the Old Norman French escauwage, examination, from escauwer, to scrutinize. The link with scavenge seems to be the idea of cleansing something.