I use window cleaner for my monitor screen, but you MUST put the cleaner on the cloth...NOT spray it on the screen.
I hosed a monitor years ago when I sprayed on the screen, and before I could catch the drips, they dripped down the glass and into the case. Fried it.
As for CD/DVD, I use my breath on them. It is recommended that you wipe them outwards from the middle - not around in a circle.
For tougher cleaning, I've got
electric disk cleaner/refurbisher