Something I regularly dispose of is drink bottles, and while they go into the recycling when I get rid of them, it is possible they do not all make it to recycling facilities. If they were to be found in the future, they would most likely be able to assume that the bottle is some form of drinking vessel. If found on its own, they might make the assumption that it was a form of traveling with liquids, which would not be incorrect, but if it were to be found with other waste objects, maybe even with other bottles, they would likely make the assumption it was not something that we cared to hold on to. If they drew the conclusion that these were bottles of liquid being sold, they might make the incorrect assumption that water was a rare and hard to find resource, since it was being distributed to people in what would appear to be rationed amounts. From there they might assume that necessary resources might have been difficult to obtain, especially if they find other food packaging, which would also give the impression of rationed items.