How To Clear Recent Apps for ICS on Android Users?

I heard that the Android 4.0 (Ice Cream Sandwich) lets you swipe apps out of the list, dismissing them permanently.
I want to know what happens at the OS level when you swipe an app out of the recent list – let's say Music app?
Does it clear the app's data out of RAM and first stop all background processes related to the app that's being stopped?
Is there any additional steps on how to clear recent apps in ICS?
