Sarah is correct. The contemporary art museum, located in the huge modern wave shaped building on the hill near Monte de Gozo, has a large multimedia sculpture made up of discarded poles.
This year they added a new feature. Pilgrims discarding their poles at the pilgrim office can choose to tag the poles with a provided card that provides contact details (name & email). I have no idea what the sculpture looks like. But the idea is interesting.
Someone comes by periodically to collect the tagged hiking sticks and staffs to bring them to the museum for potential use. Some mornings, I would come into the office to discover that EVERYTHING was simply GONE. I have no idea where it all went.
Those discarded hiking sticks and staff that are not tagged, are treated as I mentioned above.
Also, I was approached by a German pilgrim who, after riding to Santiago from Germany, specifically wanted to donate his three-year old, very expensive, German-engineered hybrid bicycle (mountain / road) to another needy pilgrim. So, I directed this fellow to take his bike to the Pilgrim House. I later heard that it was adopted onward... Success!
Hope this helps.