What should you do about surplus hero fragments?

Quiz: Recycle them to get pts which can be exchanged for Hero Frag.

Go to the Hero menu and select the 'Bag' tab. Here you can see any spare frags that you have. You can then 'Recycle' any frags that you don't need. This turns them into Noah Points.

Then go to Noah's Tavern and select the Exchange tab. There you can spend the points to by frags for some heroes, hopefully ones that you do need.