Try either WD-40 or Goof off. Do not spray on the pool, spray on paper towel, away from the pool, then gently wet the sticky stuff. Try not to get any in the pool. Use a fingernail or a plastic scraper...should come off pretty easy.
Once it is off, clean the FG with the same method (spray on paper towel) using Windex to remove the WD or Goof Off.
Do not use any metal on the FG, especially razors...