I know this is an old thread, but we do this at the Ball State Fiji Chapter. It doesn't raise a lot of money, I couldn't even give you a figure, but it raises a little at a time and is good to have as an ongoing thing. We go through a company called The Funding Factory (
www.fundingfactory.com) which collects empty ink cartridges and cell phones. They provide the boxes and shipping labels so all the chapter has to do is collect. I recommend hanging flyers or putting up collection boxes on campus.