a lot of single-use items come from fast food places, which people will eat in their cars and then just throw out the window as they drive along.
it’s a fucking sad practice but it’s really hard to get people to stop doing it, so the next best option is just to make sure as much as possible of the things you get from fast food joints will dissolve in a rain shower.
i feel like even if it’s a “remodel” that’s a very ship of theseus situation, barns are basically just 4 walls and a roof to begin with so by the time you’ve added the things necessary to make it a living space the whole thing is 90% new anyways.