How do I delete the entire history (Recently Used Items) in the dash?

how do i delete the entire history(Recently Used Items) in ubuntu

An alternative way, with a simple interface to remove all record logs of Recently Used files and applications in Ubuntu 12.04 is to follow these simple steps:

1. Click on the control icon (cog wheel on top right hand corner of display screen);
2. Select System settings;
3. Click on All Settings tab at the top of the dialogue window that opens up;
4. Select Privacy icon;
5. Select tab Recent Items;
6. Under "Forget Activities option" listed, select All in the drop-down box on the right-hand side of the option;
7. Click on Delete History button;
8. Click on Yes to the confirmation dialogue;
9. Close System Settings application window;

Job is done!