Chin Mudra is a good Mudra for meditation.
When your mind is not relaxed, start with this Mudra and automatically all the unwanted thoughts that is clogging the mind will go off. That is why this Mudra is called as Chin Mudra or Gyan Mudra.
There is nothing Gyan or wisdom as it is. There is no wisdom available (outside). The Mudra will remove the Agyanam (ignorance) in us. Then wisdom will come automatically.
Whenever unwanted thoughts come to you, be in this Mudra and they will get released.