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 The value of all these coins lost 90% even now looking at it I do not believe it is no longer valid.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?
Why would you hide or delete it? What if it increase in value over time? Just let them in your wallet and let them pump for a while you are still joining some airdrops and bounties to increase the quantity of your token that may have a value in the future. Try to do social mining as well, some good and legit projects does that even thought they are already listed at exchanges.