You can get a thing that’s like a mechanical eraser - a long eraser held in a mechanical pencil-like holder. Great for what you need, also if you get a pencil with a completely useless eraser, like some I’ve gotten.
The erasers by themselves are great! I recommend the Staedtler.
Also, if you get the Sanford Sidetrack mechanical pencil, it has a long, refillable eraser. Buy the replacement erasers for Le Clic (replacements for the long, lone erasers in the holder), cut them in half, and they fit perfectly into the mechanical pencil. Great pencil, neverending eraser.