I recommend cleaning the paddles also. I have three sets and none of them worked right when I bought them, but a quick clean and they were all as good as new. I've heard from a couple of people that contact cleaner, sprayed into the pots on the paddles will get them working without having to take the pots apart, but I went ahead and did it the hard way, just to make sure I got all the gunk out.
If you buy ANYTHING from BestElectronics, you won't go wrong. Get the Best GOLD Lifetime Joysticks. The price may seem high, but you really can't beat fully refurbed and upgraded joysticks. I rebuilt a set of mine, using the Gold Lifetime PCBs and went ahead and bought the other parts (boots, inner handles, fire buttons and springs) from eBay. It saved me a little cash doing it that way, but I already had the joysticks to rebuild. I use these joysticks all the time now and I couldn't be happier with them. There's a nice tactile "click" in every direction and the fire buttons work great. These are a more responsive than the factory sticks ever were.