I just saw an old episode of Beaver in which Eddie Haskell tells Wally that putting his car back together is “a can of corn”, in the same manner one would say something is “a piece of cake”.
I never really understood why something easy is considered a piece of cake, but now I’m really thrown by this “can of corn” thing. Huh? Where did these sayings come from?
“Can of corn” is a baseball phrase, I do believe. Let’s see…
Wikipedia says:
Former pitcher and current Giants announcer Mike Krukow, who desperately wishes he’d been born down on the farm instead of in LA, uses this phrase a lot.
Interesting! I had never heard the saying before. When Eddie said it I was like… WTF is he talking about? Oh them krazy late 50’s kids! 
I’ll expand a wee bit on Kyla’s Wiki link. One of the White Sox TV guys is fond of the phrase for a fly ball that needs only a step or two to have it drop into the glove. He explained it for a fan. Very similar to the Wiki piece, except his grocer had a long pole with a hook on the end. He’d use that to tip over the can of corn on a high shelf, and it would fall right into his hand.