This link over at MSE is really useful for checking what's the best value for your old mobile from using one of these mobile phone recycling companies. Sometimes your can get the added bonus of using Quidco as well. Works for working and non-working (although check the non-working terms for each site e.g. sometimes cracked screens and water damage aren't covered).http://www.moneysavingexpert.com/phones/mobile-recycling
Better than hanging about gathering dust in your drawer!