Probably says to not throw in trash because they use lead in the solder.
Proper disposal is to send to an e-waste recycler. However, if you are very conscious about the planet and were things go, verify where they send their scrap before hand. There are some places that just strip all the wires (copper and aluminum basically) and send the boards to the dump anyways. (this has been documented by Veritasium on Youtube and others)
Or give them to some technician/electronics enthusiast, I think the two little SMD chips are 8205/8017/or similar... I would unsolder them all... and you'd have a new friend
Or put them in a box and put them on EBay, boxes of 50 or 100pcs... I'd try and make 40$ out of them LOL