Organise a yearly stationery amnesty:

"An event where everyone in an office or building is invited to get rid of their unused and unwanted stationery (pens, staplers, envelopes, etc.) so it can be collected and reused. This saves money, as you don't need to buy new stationery, prevents items from going to landfill unnecessarily, and frees up space."

(Rémi Césaro, Resource Efficiency Consultant - Zero Waste City)

Here are 4 steps to implement your stationery amnesty.