Well, it is pretty hard to get the M14 handguard off without removing the op rod. But once that is done, just insert any small punch or other tool (yes, by no coincidence, the bullet point of a ball round works fine!) in the holes in the handguard clip and push out and toward the top of the barrel. Do one side at a time. When both are free, the handguard comes right off.
For the wooden handguard of an M1, it is better to get a tool to avoid chipping or splitting the guard, but for the fiberglass M14 handguard, there is no worry.
Jim