Keep those cartridge contacts clean,
And never shall you see
A flashing grey screen.
My recently eBay’d copy of The Legend of Zelda for the NES arrived in the post today, woo hoo! What’s the first thing I did? Why I took it apart and cleaned the contacts of course. With clean contacts all my NES games work beautifully on a NES that has lived in a garage for the better part of this millennium. Even without replacing the 72-pin connector. I’m using a cleaning kit I picked up from Nintendo Repair Shop, it’s worth it just for the proper screw driver bit to take the cartridges apart.