To make a long question short: What's the proper way to replace a rubber spring (inverted cup-like thing) under a keycap, specifically the Tab key on a unibody design MacBook Pro or Air?
Details: I just bought a used MacBook Pro (so it's out of warranty), and noticed the Tab key felt spongy. Also, after first opening up the laptop, the key seemed to be stuck down until I tapped it a few times.
I had a replacement rubber spring from my old MacBook, so I tore the one off the new laptop and put that one in its place, without gluing it down or anything. Right away after that I noticed that pressing Caps Lock would sometimes trigger a tab; maybe one time in seven or eight presses. Worried I had shorted something, I shut down, repositioned the spring, and booted back up, and things seemed normal again.
Satisfied with the way the Tab key was now behaving, I decided to superglue the spring as instructed on laptopkey.com:
Squeeze a small amount of super glue onto a sheet of paper. Then dip the edge of the rubber cup into the super glue. Then place the rubber cup in its place. Let it dry. You want to have the minimum amount of glue on your cup, just enough to make the cup stick while installing the hinges onto your keyboard.
I let the glue dry for a few seconds before putting the key cap back on, and while I was waiting I pressed on the spring a few times to make sure it was still springy. Unfortunately, I got way more glue on the spring than I had intended, and it oozed out a little. I also later realized the spring was displaced a little from where the original one had been (as evidenced by the still-visible metal circle under it).
When that was done and I booted back up, I found the key to be better than before, but it still seemed to require a little more pressure than other keys, and it didn't make the same clicky sound when I hit it. I decided to live with that. However, when I opened the laptop again this morning, I found that the Tab key, although it still works, moves up and down very slowly; it takes a second or two to pop back up after I press it. There really isn't any tactile feedback to speak of, so it's worse than when I started. Tapping it quickly a few times didn't cause it to release, the way it used to.
I'm about to order a new rubber spring and hinge kit (and maybe a key cap). How should I install the new spring to make the Tab key act like new again? Is there a specific way I should clean off the old rubber and super glue?