Just hold the tokens you have now. Never throw the private key away. You have to understand that even though the price of some of these coins are terribly low, you never, ever know if one might moon for some reason. Sure chances might seem slim. But I know a guy who had ten dollars worth of coins, and since he didn't care much about the ten dollars, he checked years later and it was was worth like $2,000. Imagine had he invested $1,000 though.