Go to a high end glazing shop.. If you own a business go to CRL for anything glass related.

Aluminum is so soft I wouldn't touch it with sand paper.. Clay bars that are used for high end cars would be the best... Buy some 3m protective coverings

Moisture got in... Try to fix with new cable

Isn't this common knowledge? Buy a ^$!& cover for your cards or use RFID cards... My fobs, cards are not affected because new technology is RFID.. And it's not new tech.. If your card is not working 99.999 % of the time it is the stores terminal. They are never maintained or cared for... Stop blamin mystical magnets for your cards. I'm at a hotel now.. My room key made love to the spline of my cover ... And no problems If you really could mess up cards.. I would place rare earth magnets across the city and watch the banking industry fall at my hands... Muhhhahah ... You see how silly I sound.. That's how I feel after reading some of these answers