Our special sand erasers were made specifically to erase colored pencil cores including Blackwing Colors and Blackwing Red and Blue. Set of 10 replacement erasers. Blackwings have always been known for their iconic square erasers. To replace your eraser, slide the eraser and clip out of the ferrule, remove the clip from the old eraser, place the new eraser into the clip, and insert the new eraser and clip into the ferrule.