I know, weird topic that came up in the breakroom today, and thought I'd get the e-Hellions in on it.
We have trashcans in our breakroom that have flat tops on them that hinge open in the center. If you drop something heavy enough in near the center, it opens and things fall in. They are set at a small angle, so there's a little 'well' of space at the top, where small items can sit without falling on the floor. Obviously, since the top is in contact with everything that falls through, and it is in the breakroom so the trash is often food related, the tops aren't the cleanest things in the room - and most folks would actively avoid touching them.
The problem happens when you have something lightweight - a napkin, an empty paper plate, etc. Is it rude to leave it sitting on top of the lid, so that the next person that drops something heavier in will 'clear' the lid? If you were to poke things in, then you'll end up washing your hands, drying them on a paper towel, and repeating the cycle again, so this isn't a good solution, but I was told by one of the bossier ladies on my team that it was "soooooo ruuuuuuude" to not poke a paper towel down into the can, even though she couldn't come up with a better solution.