If you have toothpicks, you can use these to pick off larger pieces of corrosion from the springs.

If you have electrical tape, cut it into small squares and cover openings to the circuits inside to prevent water from getting inside. Dip the q-tips into the solution and start scrubbing. They are not sturdy when wet so you will need a lot of them. I find it useful to clean with one end of the q-tip and dry with the other; after all, you don't want to get the electronics wet inside. That is why q-tips are good since they can't hold enough water to really drench things. In between scrubs, you can use a toothpick to get off more loosened gunk.

If you have the leeway, use the paper towels. They are larger and slightly more abrasive than the q-tips. Be ABSOLUTELY sure that they are not soaking wet as you do not want to get the delicate circuits inside wet (yet another reason to use electrical tape). Repeating what you did before, scrub off the the corrosive chemicals and dry. You may hear fizzing as your solution reacts with the leaked chemicals.

You need not be perfect with your cleaning. You only need the parts of the metal that touch the nodes of the battery to be clear enough to conduct electricity. The metal underneath the corroded area will still conduct just fine.

**Be careful not to touch your face, eyes, mouth, nose, etc... as some of these chemicals are very caustic! Plastic gloves, or even goggles, would be great for safety here.

If you are not having any luck, see the next step.