Try spraying 3M77 spray adhesive on the underside of a small piece of spoil board and wave it around in the air for 30 to 45 seconds to dry it. (Do not spray the granite.) It will be very tacky. Press it down firmly onto the granite. After an hour or so, see how much force is required to pry it off of the granite. It should release cleanly from the granite but the spoil board will still have all of the adhesive on it. None should be left on the granite. It should require some effort to pry it up. 3M77 will make the spoil board act something similar to a Post-it note.
For the full size spoil board you can apply spots of 3M77 instead of spraying the entire surface.
You can remove any adhesive that does stay on the granite with PrepSol or similar solvent.
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