Ok so I bought a few games from a guy at a flea market and all of them worked after I cleaned them. One however which is Kid Icarus, will boot up and play just as it would normally except the screen is all pixelated and the sprites are a mess. I cleaned the part of the cartridge that the nintendo reads with window cleaner and q-tips until there was no dirt left and it still does this problem. I tried it on 2 different nintendos and it does the same for both. I posted some screenshots below. I was wondering if there is an easy fix for this or am I just better off finding a new copy?

Start up screen at boot-up
http://i1160.photobucket.com/albums/q494/JBishopNES/photo4.jpg

Title screen
http://i1160.photobucket.com/albums/q494/JBishopNES/photo3.jpg

Game screenshot (Pit is the yellow cluster of dots and the enemies are the white blobs)
http://i1160.photobucket.com/albums/q494/JBishopNES/photo2.jpg

http://www.youtube.com/watch?v=D_YI4UTo0II
Link to how i clean my nes games.  I have never had a game not work after using this method.  Good luck sir

Dead thread. BUT..Disassemble cart. If there is a capacitor inside. Replace it. Use a large rectangular eraser to rapidly rub out the gold contacts (back and forth) until heat is generated. Blow away or wipe off little bits of eraser left behind.