I feel like such a chump. Several years ago, I hadn't planned on buying anything at a Tupperware party that I had agreed to take place in my home (yes, they still exist). But then the hostess told us about this special black-and-white can opener that was available. It didn't cut the top of the can, it popped it up leaving no sharp edges. Well, I immediately imagined all the fake products** I could make with those now-reusable empty cans and bought it for $35. Cut to today: this video shows that any old ordinary can opener can essentially do this same thing by using it horizontally! Ok, to be fair, I haven't tried this new method (mainly because I no longer have ordinary can openers). It could be that it leaves sharp edges but I don't think so. I think my life has been a lie.
**On my website, there's an example of one of my empty can pieces. It's called "Mermaid in a Can."