I'm talking about people spitting in front of the elevator doors, people opening their mail in the common building area and immediately throwing the envelope on the floor, people finishing their drink in front of the building and discarding the bottle by the side of the entrance door

We don't need alien tech to solve these, it's 100% an education issue.

They should be educated, sure, but this can't be an education issue. Rather an issue of crappy upbringing and low intellect or, when it's a cultural thing, crappy culture.

This depends if you only understand learning in school to be education, or if you mean the whole education that a pupil underwent, which I think was the case here. To me upbringing is another word for education.

Then I would use the legal and executive system, to deal with this people. That's why they exist after all.