ONLY If you used unsalted butter, optionally reserve the milk solids & water. You can heat them in a shallow pan first to drive off the last of the water, then continuing to allow the milk solids to brown a bit. They have various uses like dressing vegetables, mixed into mashed potatoes or rice, or kneading into bread dough. Mixed back into the butterfat they take on an amazing flavor profile and consistency, though it lowers the smoke point. If you used salted butter, once the water is driven out the milk solids they are so insanely salty they are not practical to use.