Why you don't sell them?
There is a market where you can buy and sell testnet coins, the price is low, close to 200 satoshis, but as we know this coins were not supposed to be on markets, but there is a chance to sell them, if you have a big amount you could walk away with some cash. The market that I'm talking about is the next one:
https://altquick.com/exchange/market/BitcoinTestnet3So, think about it, and if you still want to give them away that's your call.