My son helps me place zip lock bags under car windshield wipers. In them, they have a smiley rock & poem, book mark and a blank home made card with a blank, stamped envelope to encourage the recipient to send someone some postal message.
One day, it was raining but we put the zip lock in it’s place all the same and I went into the shop. My son was beside the car to witness that the lady was rather short and didn’t see the package, put her wipers on and the lot disappeared under the bonnet. We only hope it wasn’t too damaged & will be retrieved on the next vehicle service. – Caron 😉