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 Try this when your games just won't work right or not at all:

Take a q-tip and dip it in rubbing alcohal. Rub the metal game connectors on both sides and apply a great deal of pressure. Now use a dry q-tip and rub the connectors again using the same amount of pressure. Repeat this until all dirt is removed. Let it dry and it should work. Be sure to do this every now and then with your games to insure you don't transfer dirt to your system.

To make it easier to see what you're doing it's good to open up the game cartridge. It allows you to be able to see what the connectors look like and you can see how dirty they are. also i find that if u let the game sit for a few min after you clean it to give it time to fully dry.

 Here is a in depth guide to cleaning games. Step one get your supplies together.

 Step two dip Q-tip in alcohol.

 Step 3 rub Q-tip up and down and back and fourth very hard across contacts.

 Step 4 repeat step 3 on back of game.

 Step 5 rub front and back of contacts with dry Q-tip apply more pressure this time untill all dirt is removed.

Your game is now clean. You may have to repeat this process a few times depending how dirty your connectors are. If you have the 3.8mm bit you can take your game apart and clean it the steps are the same, but this allows for better cleaning. The bit can be found on Ebay.

All this information and more is provided at my e-Bay forum named : dkoldies Nintendo NES Info Forum