Exchange unwanted items for galleons

I've noticed that over time we tend to accumulate a lot of items either through card prizes, point prizes or items we have to buy for the new school year. Now I feel it just goes to waste if we throw them away as we did spend money on them. Is it possible to return/exchange them for say 30-40% of the price that we purchased them for? So that we have the chance to purchase new items or even wizard cards.