Ideally, you would dig under it with your thumbnail and gradually work it loose. Your thumbnail is unlikely to scratch or gouge the finish. If that doesn't work, you could try sanding off the old rest and glue, being careful not to sand down into the finish. I would imagine this would be a tedious process. There are probably chemicals, like MEK, that would quickly remove the rest and glue, but they might also remove the old finish just as quickly. I can't imagine why anyone would use a permanent glue on an arrow rest. I've found that double sided carpet tape holds well and is also easy to remove.