Now for the hold your breath part, reassembling the pruners. Simply slide the two parts back together, position the spring and replace the nut or screw. Test the pruners to be sure you haven't over tightened and that the blades move correctly.
Once the pruners are reassembled, give all the moving parts a spray of lubricating oil. Also coat the blades, to prevent rust. Wipe off the excess. And that's it!
You should clean and sharpen all your garden tools at least once a year, at the end or beginning of the gardening season. It would be even better if you did this monthly, especially for tools you use regularly, like pruners. The more you do it, the easier it becomes and the less time it will take. And I promise you you'll notice a big difference when you go to use your sharpened tools.