In truth, there isn't much you can do if your altcoins don't worth anything in your wallet. All you can do is to continue holding it until it can be traded for something of value. If you're lucky and you find someone willing to buy your coins (perhaps they forsee its price going up in future), you can sell to them but then again it's a risk because if the buyer ends up being right, you'd feel stupid for selling to them cheaply.