is there any coating or other suggestion to avoid the same
There are three things that you need to keep an eye on if you want to keep it fresh 1Light 2Moisture 3Temperate You'll want it to be dark, dry, and cool or cold if possibleI kept some in foil in my wallet for only a couple of days, and I assume the temperature was what killed itFoil is good, but I would put that foil in some kind of container and put it somewhere coolA fridge or freezer is ideal, but if that's not possible and you're not keeping it for that long you should be fine either way.
Nope - that's part of using oneSome people pick them specifically because they like the look of the well-worn aluminumIf it really bothers you, you can polish it off with a soft rubbing compound (available at a harware store) but it will be a lifelong taskSeriously, if the look of scratched aluminum bothers you, leave it at home where it's safe and get a leather caseOr carry it everywhere and let people wonder in awe about the exciting life you lead when they see all the amazing scratches.
