You are right to mention cookies, because Google's position is that it will show that bar if there is no cookie saying you've seen it before. Cookies can be cleared in numerous ways, including: * Allowing sites to set cookies for the current session only (not persistent) * Using the "Clear history when Firefox closes" feature (with cookies on the list of things to clear) * Using automatic private browsing * Add-ons that clear cookies * External software that clears cookies Another approach is to use an add-on or custom style rule to banish the blue bar. This thread has suggestions along those lines: https://support.mozilla.org/questions/1049226