No need to throw them away.
Most of us wouldn't even notice.
The collapse of the Rapanui on Easter Island was gradual and not sudden, and many factors came into play to trigger it
Identificar la falsa moneda en medio de las auténticas requiere a veces no poco ingenio
The Stone Age inhabitants of southern Africa used the mixture to create comfortable bedding and protect themselves from insects.
That's what may have occurred in New Zealand.
Definitely not aliens.