Instructions
Blow on the game cartridge before placing it in the console. NES game cartridges attract dirt, which you can often blow off.
Dip a cotton swab into a window cleaning solution. Rub the swab over the game's contacts to remove any dirt buildup. Repeat until the swab shows no signs of debris. After cleaning, rub a fresh cotton swab over the contacts to dry them.
Use a nail file. If the system has trouble reading the cartridge, rub a nail file lightly over the contacts. Apply light pressure to avoid irreparably damaging your game.
Check the console. If you still experience problems with your NES games, clean the game console. Remove all the parts and clean the pin connector with rubbing alcohol.