I recently threw away some items to thrash bin. I put like 10-15 satchels filled with big amount of wood scraps and some other stuff. Items were gone but most of them spawned as pile near thrash bin. Because pile contains 1k items, I take 100 of them and put again to the thrash bin, where they take damage and vanish. After that again new stuff is spawning in the pile up to 1k items. I don't know if these items are the ones I threw freshly to trash bin or these over 1k that didn't make in earlier.
Also don't know if location of thrash bin have something to do with it.
Edit:
just checked: new items spawned in pile and again there is 1k items before the ones in thrash vanished. That would mean that they are from the first action, where I put over 1k items.