How can I empty the trash from all users at once

My MBP is running slow, possibly because I have less than 20% of my internal disk space available. First thing I want to do is empty the trash. With the wife and kids, that is 5 user accounts.

Is there a way to empty all of them from the Manager account?

I did a Google search as well as on this board and, surprisingly, did not find any answer. I've got to think others have run into this...

Thanks for any help.

Bo