To avoid the cosmetic glitch of the trash appearing full after using testuser's script, you should add this line to the end of the script: osascript -l AppleScript -e 'tell Application "Finder" to empty'
An awesome utility, everyone should get is Xupport. It give a nice clean UI for many task that would normally require gettin command line jiggy. It of course has empty trash regardless of privis as one of it's features.