Bubble Style Carb Cap
This Dankstop Bubble carb cap is meant for a thermal banger, but can still be used on any nail to help from wasting any product. Because of the ball shape you can move it around and it will still fit on your nail while you move it around. One end works as a handle and angle the ball however you like while the other is getting the concentrate from the corners.
Coming in a variety of colors you have the option to pick one that matches your rig.