Hey guys I have a few lovelaces (like 200) in a couple of old wallets I don't use anymore. The trouble I have is they are still delegated to a stakepool earning rewards and I can't work out how to undelagate them ! Can anyone help ?

Recover the wallets in Eternl or Yoroi and un-stake / deregister the wallet you can do that from the staking section in Yoroi or the settings tab in Eternl (at the bottom) make sure you have a positive balance in the wallets before you do to pay the transaction fee to claim rewards and submit the transaction. There has to be a positive balance to claim the rewards