CD Skipping

Some more intense cleaning might do it.
Dust isn't very friendly to stereos, and it doesn't stay only on the surface.

So, go get your favourite screwdriver, unplug it from the AC, open the covers and start cleaning, vacum, gentle brush, whatever it takes to get the dust out while not moving or misplacing any of the components.

About the cd specifically - more often then not when i had cd problems it was solved by cleaning dust of the lense. locate the laser lense and check to see if theres any dust accumulated on it. If there is, very gently brush it off, if not check for anything else around there that looks out of place before closing the cover and trying to play a cd.

make sure you try more then 1 cd, or more then 1 cd format. Don't try only burnt media.

You didnt mention much about the symptoms, but here's a link to a good guide on diagnosing shelf systems -

http://www.fixya.com/ThreadView.aspx?thi...

good luck