How can I clean up the Open With.. Menu

I've been using my desktop since the release of 10.10, and as per usual its very cluttered. I spent a few hours today tidying the system, and I've found a really annoying area that I'm unaware of how to fix. The Open With... dialog contains several duplicates and even bunk entires. How can I remove these?

EDIT: I've also stumbled across a great tutorial on this subject http://greeennotebook.com/2010/11/clean-up-the-open-with-menu-in-ubuntu-10-10/

You can remove the duplicate entries in ~/.local/share/applications

right click on the file . select the properties and click on the 'Open With' tab. Select the application you want to remove and click the button 'Remove' to remove that item from the 'Open With' menu.