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 The value of all these coins lost 90% even now looking at it I do not believe it is no longer valid.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?
Just create a new wallet, or you can send all those tokens to a new address. There is no way you can delete or burn them, it will last forever
Many above have already given the answers but I think that the best way in this situation is really creating a new wallet.Or just sending the necessary and valuable coins to a new wallet.