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There are many ways and many apps to do this. Quick, easy, painless way to do it is to go go versiontracker and download "Trash It".
 
No need to download anything to do that . . .

The trash can has a little know option that allows you to force empty locked items.

Clipped from Help: "If an item in the Trash is locked, press the Option and Shift keys when you choose Empty Trash to delete it."
 
another way...

pull up a terminal, type "rm -r .Trash/"

but don't get in the habit of using "rm -r" command too often. it could have some serious consequences. ;)
 
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