Dad kept his WWII one, but Mom tossed it out when she got an electric can opener for Christmas one year. Dad had been discharged from the Navy for almost a decade at that point, and Mom couldn't understand why he got upset that she threw the thing out. She kept asking him why, and the 3rd time she asked, Dad got teary eyed and Mom told me and my brother to go to our room.
The story around Dad's WWII can opener is still a mystery, but me and my siblings have theories. Mine is that it "belonged" to a buddy of his who was KIA. I know they weren't issued to individual soldiers, but one of the only 2 personal war stories Dad ever told me was about a buddy of his who got shot right after opening a can of hash. Dad was sitting right next to him and they were going to share that can of hash. Plus, being shot at was totally unexpected because they were on a supply ship, and there was an international agreement about not shooting at anyone's supply ships...same as not shooting at medics.