Ya, you probably overpaid. You can find one on ebay for a buck with a couple more for shipping.
As for cleaning... I use Q-tip and alcohol. It works pretty well, but I have been looking for a better way to do it as well. I was going to post here, but I guess this fits right in. The principle is ok, but the problem is that the q-tips are just to damn flimsy. I think that alcohol is definitely the correct cleaner (the higher %, the better), but does anyone have any suggestions on a replacement for the q-tips? I am about to go through and clean up my collection and I am not looking forward to cleaning 1200 carts with freakin' q-tips.
BTW, we are talking about cleaning the contacts here. Cleaning the cart itself is a whole other story.