I usually try to travel light and not carry too much with me, but I do bring some needed consumable that I deplete during my trips, leaving some litter:

>antiseptic alcohol wipes and surgical tape (having scars on your cheek sucks ass; as soon as they heal you get ingrown hairs and they get infected)
>bottle of lighter fluid
>decongestant nasal spray (goofed up and damaged my mucous membranes some years ago, I need this)
>empty plastic bags
>tin cans from my emergency canned food
>used up lighter
>my disposable cutlery


I feel dirty carrying it with me in my backpack, and so I prefer to get rid of it. I tried burning things as I went along once, but was almost hit when the apparently not so empty bottle of ligther fluid suddenly burst on the fireplace.
Now I usually tuck things into crevaces, usally next to rocks, then put some moss on top to prevent animals from getting to it or the sun from shining on it.

How do you folks do it?