I have had the same problem since I installed Microsoft 2011 for Mac on my system, overtime when I shut down my mac and come back to use it there are recovered files in my trash can. The way I fixed it was by going in the Microsoft word and goto the preference setting/personal settings/feedback it will open a pane for the customer experience improvement program, if you have checked yes you will need to check no and then click on ok for it to change.
The next step I had to do was open finder goto devices and click the on with you username in the window you will need to click on Macintosh HD / Library / Application support / Microsoft / MERP 2.0 you will look for Microsoft error reporting click on it and on the top bar in the upper left hand conner you will see Microsoft error reporting , click on it and goto preferences a small window will open and you will see enable error Reporting uncheck that if has been checked close all the window panes out and restart you OS. Your trash bin should not have and recovered files that were produced by the Microsoft Office 2011 program.
I have not had any issues since doing this over two weeks ago and do not keep having the constant annoyance of emptying the trash bin all the time, I hope this helps .