2006 Altima 2.5L Automatic

First off, I must say that I'm not sure if this is a problem specific to the car or just in general. Anyway, I opened the hood of my car the other day to find that the battery terminals were covered in corrosion. I took them off carefully and used a wire brush and 150 grit sandpaper to clean the clamps and the posts. After returning them and tightening them down the car started fine and I parked it. The next morning, however, I noticed that my clock kept changing times randomly and some problems with the lights on my dashboard. I have no idea why this is happening yet I'm almost certain that it was a result of the battery cleaning. What can you tell me about it? Thanks
-Sheafromme