I've tried many different trash can designs, but every single one has had at least one
idiot wolf jump into it and die.
The first trash can I came up with is a pressure plate that opens a trapdoor with lava under it and an upside-down slab for safety. Obviously, wolves can still fit through there, and when I built this I didn't know that wolves are incredibly stupid.
I also tried one where you throw the item over a block and it lands on a cactus, but for some reason a wolf walked into that also.
The latest one is by far the safest, and the wolves mostly stay out of it, but recently one wolf pushed another one into it and the wolf didn't get back out. Sadly I didn't remove the water quick enough and it drowned. :(
This one I didn't create myself. Watch this video to see how it's made. (It's the last one that he talks about.)
Of course the best solution would be to make wolves smarter, but until that happens, is there a way to make this even safer without taking up more space? If you have a different design that you think works better, please share it.