I clean my Activision carts a few times and when I put the cart in, I only go in about half-way or most of the way in. Turn on the system and usually the abrasion of doing that works. I do it a few times and it almost always works. After I get them to work, then putting them in all the way usually works with no problems after that. Make sure that while cleaning the board, clean the board all the way down to the bottom. Very rarely I try and try and finally have to resort to deoxIT and that does the trick also.