What should I do with these mezuzahs?

I am not Jewish myself, but I am looking for advice on how best to handle a situation respectfully. Recently, my partner and I moved into a rental house, which came with mezuzahs installed at the front and back doors. We asked the landlord about them, but they appear to have been left there by a former tenant, who we have no way to contact. Since neither my partner nor I are Jewish, it seems disrespectful to keep them where they are, but since we cannot return them, we are faced with the issue of what to do with them. Keeping them feels wrong, but so does just throwing them out, so we wanted to consult the Jewish community. Any advice that anyone can offer would be greatly appreciated.