The wat I clean contacts is I cut off a piece of a cleanwhite t-shirt and an expired credit card, any card you don't want anymore. I wet the peice of t-shirt in alchohol, stretch the peice of t-shirt on the card, and push it into the cart slot. All around. To get to the pins, you're supposed to have a small flathead screwdriver and put into the very ends of the black cart slot part, and the door to the pins will open. After, just take another peice of shirt and repeat, without putting on alchohol to dry. It does wonders.