On this Assassin's Creed Valhalla page, you will learn how to downgrade unused gear (Downgrade Gear option) and recover invested resources.
If during your time in Assassin's Creed Valhalla you upgraded many weapons and armor that are now unused or you want to change your fighting style, you can easily recover the resources you invested. However, this option is not for free.
To do that, you need to go to the blacksmith Gunnar, whom you will find in Ravensthorpe. From the available tabs, select Downgrade Gear and find the item you want to downgrade. Each downgrade costs a certain amount of silver (depending on the quality) and resets the item completely. However, in return, you get back the raw materials that were used to raise the item to a certain level.
You don't have to manually remove runes out of items - this will be done automatically.