When you choose to begin Presentation Mode from your dashboard, this will enable you to present in person with clients without having to be concerned with any private information being displayed.  When in this mode, unit price and product descriptions will not be active.  You can exit the mode from your dashboard to continue working as normal.  When you enter this mode, that information is hidden, no matter which projects/boards you are viewing.

To activate this mode, go to your ACCOUNT Dashboard and click the eye symbol.  When you are ready to end the mode, just reclick.