I used to do Air drop and bounty. Get all coins in time when the market is down. The value of all these coins lost 90% even now looking at it I do not believe it is no longer valid.
I cannot sell them because no one buys them, and its value can only be enough to transfer to exchange.
So do you have a way to hide it or delete all the coins from your wallet?
You cannot delete or hide coin that you have in Myetherwallet, because there is no myetherwallet system to delete or hide coin that you have, but if you really want to eliminate them, so I advise you to create a new wallet and transfer it to a new wallet.