If you're playing on old ark mobile and casual mode the best way to farm polymer is to get 5 snails, 1000 metal, 200 sparkpowder, 500 crystal, and 200 electronics. Then whenever your snails are done producing 500 organic polymer and 500 achatina paste you can use those along with the materials listed above to craft 2 chemistry benches, then destroy them to get all the materials back plus 500 regular polymer and 500 regular cementing paste. This will ONLY work if you are playing on casual mode which is only available in old ark mobile during the creation of your game.