I was excited to find a base with 500k elixir, gold and 4k dark elixir, and I had my strongest army composition. I was disappointed however, when 20 wizards, barbarian king and heal spell was unable to take out the Valkyrie in defending clan castle.
How can you attack Valkyrie? Usually I try to make a circle around the defending troops, but this doesn't work as they would move in so they were close together and the Valkyrie would spin around and take them out. With wizards their range isn't super long and they take time to reload, and Valkyrie are so fast it was like they didn't have time to attack.
I guess the lesson is to always carry a poison spell.