Originally Posted by
OldSchoolGamer quoting some other article
You can try cleaning the contacts on your atari itself. Take a piece of 100 grain or finer sandpaper and cut off a square using scissors to fit the slot in the atari in the middle of the atari cartridge slot between the two prongs. Rub the edges and front of the sandpaper with your fingers to remove any loose grains of sand. Gently insert the sandpaper into the slot. Do not rub side to side, just in and out 4 or 5 times, then flip it over and do the contacts on the other side.