These phones are a kind of non-regulated e-waste.
Blue Bins & Chutes
Do NOT put in e-Waste bin or blue bin! Small electronic devices like this are Non-regulated e-waste which cannot be put in the blue bin or the 3-in-1 eWaste bins.
However there are special bins for such items! Unregulated e-waste bins are dotted around the island. See the providers below for more info on these bins.
Metalo Non-regulated e-waste bins
KGS Non-Regulated e-Waste Bins
In addition to non-regulated e-waste bins, there are various places you can take such electronic devices.
Tzu Chi Sustainability Day
Cash for Trash
Freecycle / Give Away
If the item is still in working order, consider giving it away online.