Explanation: It's impossible for cement trucks to dump out every last drop of the gray mush. Over time, the barrel becomes coated with hardened cement, and it's someone's unpleasant job to chisel it off. MythBusters fans asked Jamie Hyneman and Adam Savage whether a stick of dynamite could perform the same cement cleanup duties without the added elbow grease.
To test whether the explosions could shake loose the cement, Jamie and Adam consulted a pyrotechnic and set off a series of explosives inside two dirty truck barrels. Cherry bombs, M-80s and a 1-pound (.5-kilogram) black powder bomb were wimps, barely scratching the cement surface.
Undeterred, the MythBusters brought out the big guns and detonated a stick-and-a-half of dynamite in the middle of the barrel. High-speed footage from inside the barrel showed the rapidly expanding air shaking loose the cement slab. That single explosion didn't dislodge the entire chunk of cement, but it released enough to establish the myth's plausibility.
However, until cement truck cleaners can get their hands on dynamite legally, they'll have to keep chiseling away.