Hair dryer to heat it, then start pulling carefully without tearing?
That’s how I do it on repairs. I clean up the residue with a plastic putty knife and paint thinner. Wash the area with window cleaner after the thinner. To reuse the pad, get any sand/crap off the adhesive side and re-glue with contact cement.
place board squarely on heavily used doorway and insist that all entering wipe their feet scrape heartily on the surface to remove heavy agregate from their hobnail boots and golf shoes and football cleats and track shoes the pad after being repeatedly stomped should be removed in about a week, just enough time to build a good board…ambrose…isnt sweeping a lack of technical riding sensibilities under a gllue down tail rug poor housekeeping and that rug security blanket thing weighs more than mr. jones’ wonderful board en todo revolt credible skilled riders