I was told that foil disposable pans should not be squashed on Shabbos (to make room in the garbage bin). Is that true for other items like tissue boxes, cereal boxes, pop bottles, etc? what about if I am squashing it and then resetting it to its original shape to make a new k’li to reuse right then?

Horav Shlomo Miller’s Shlit’a opinion is that indeed foil disposable pans should not be squashed on Shabbos, as it may be considered braking or destroying an utensil which is prohibited. On question 431 regarding if one is allowed to crumple up a disposable aluminum pan on Shabbos, we wrote: “Shulchan Aruch (O.H. 314: 1 and Biur Halacha) rule that there is a rabbinical proscription of destroying utensils on Shabbos. However, on a disposable utensil or “keli gorua”, Poiskim maintain that there is no prohibition (Binyan Shabbos 2 p. 173). Poiskim disagree whether aluminum pans are considered utensils for Tevilah requirement. Many maintain that they do not. (Igros Moshe Y.D. 3:23, Minchas Yitzchok 5:32, Teshuvos Vehanhogos 3:259, Oz Nedberu 7:71, et. al.) Others see them as proper utensils which require immersion (Mishneh Halochos 7:111, Emes Leyakov Y.D. 220. see Tevilas Kelim p.233). Horav Shlomo Miller’s Shlit”a opinion is that if the aluminum pan would generally be used a few times by others, on the onset, one should avoid destroying it on Shabbos, unless it is necessary for cleanliness, as would be the case, when you try to fit all the waste in the can and close the lid, to avoid smells or insects. If the pan is burned or soiled and most would not reuse it, it could be crumpled as you would do with paper disposables. Other items like tissue boxes, cereal boxes, pop bottles, are similar.