I have a few games that refuse to work. I bought them at a thrift store not to long ago, so I decided to clean them. No matter what I do and no matter how many times I clean them, they just up and refuse to work. Shinobi shows a black screen (I got it working ONCE), but R-type just blanks the screen for a split second and then doesn't even show a video signal. I've cleaned both carts with alcohol and emory board (a lot of people hate this, but it does work. no, I haven't scrubbed the pins off the cart) and neither seems to work.

So, what can I do? Are there any other tricks I can try? I've never had a cart that didn't work after this much furious cleaning.