seems latley ive had alot of NES controllers crap out on me lately. Besides the fact they are all about 20-30 years old what may be causing them to crap out. ive opened them, cleaned everthing with some rubbing alcohol , nothing seems to get them to work. i researched online and one site says to clean the contacts with sandpiper. i tried this on one controller, it ssemed to clean them up and brighten them but nothing works. i tried the same controllers on different NES and i confirmed it was the controllers. what gives? just old age or is there something more to this?