If you have something in the trash that just wont flush, click on the trash can, hold the option button down and click empty trash. I had some files, even locked ones that were deleted this way.
im surprised that Thrash It didnt work. Here's how to do it in the terminal, which should work:
Ok so, in terminal type "sudo rm -rf ~/.Trash/*" (you will be asked for a password) and double check you typed it correctly, messing with sudo can ruin your stuff if you're not paying attention.