I've played through twice and both times there are a couple items that I'm pretty sure you're just supposed to sell for small amounts of gildar... Demon Horn and... I cant remember the other because I hadn't even thought of posting about it when it happened.  Anyway, you can go to your character screen and 'use' them instead of selling them but it doesn't have any apparent effect and the item disappears thereafter.  I dont know if it's doing something that I'm just not seeing but it doesn't seem to have any effect other than shorting me the 25 gildar (which is sort of irrelevant by the time you get demon horns usually).