The right sign for "erase" is going to depend on your context.
Erase as in: Erase a blackboard:
If you mean "erase" as in "use a pencil to erase your mistake," then
mime the action using a modified "X" hand to represent the eraser
side of a pencil.
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American Sign Language (ASL) online at American Sign Language University ™
ASL resources by Lifeprint.com © Dr. William Vicars