Backlit dimmer in certain spots on the keyboard after a coffee spill

Hi All,

I spilled coffee on my MBP Unibody '08 about 10 days ago. First I was happy to even see it work after such a disaster, but then I noticed the MUTE and the right OPTION key didn't work. Also, there was an odd observation I made: the keybaord was not backlit evenly no more. In the middle the keys were shining as brightly as usual, but then to the left and right other keys seemed dimmer.

Today I used the "teardown guide" and went all the way down to the keybord. I peeled off the background of the backlit, I cleaned the transparent sheet with all those dots on it, I put it all together again... BUT THE PROBLEM persist. I think I did improve the effect a little bit, but it is still not perfect as it was before.

My quesitons:

1) is it even possible to fix such a problem (or am I just lying to myself my actions brought some improvement)

2) If I need a new keyboard, would buying one on eBay work, because I've heard contradictory comments about being able to replace JUST the kybrd.

Thanks.