About your cache, cookies and browser history: 

• Each time you access a file through your web browser, the browser caches (i.e., stores) it. Thus, the browser doesn't have to newly retrieve files (including any images on the page) from the remote web site each time you click Back or Forward. You should periodically clear the cache to allow your browser to function more efficiently.
• A cookie is a file created by a web browser, at the request of a web site that is stored on a computer. These files typically store user-specific information such as selections in a form, shopping cart contents, or authentication data. Browsers will normally clear cookies that reach a certain age, but clearing them manually may solve problems with web sites or your browser.
• A browser's history is a log of sites that you visit. When you press a browser's Back button, you are moving back one entry the history log. Browsers will normally clear history at regular intervals, but you may want to clear it manually for some personal reasons.

To clear your cache:

Firefox 3.5 and above for Windows

• Click the menu button and choose Preferences.
• Select the Privacy & Security panel.
• In the Cookies and Site Data section, click Clear Data….
• Remove the check mark in front of Cookies and Site Data. 
• Unselect "Active Logins" if you do not want to clear your saved passwords.
• With Cached Web Content check marked, click the Clear button.
• Close the about:preferences page. Any changes you've made will automatically be saved.

Chrome

• On your computer, open Chrome.
• At the top right, click More .
• Click More tools  Clear browsing data.
• At the top, choose a time range. To delete everything, select All time.
• Next to "Cookies and other site data" and "Cached images and files," check the boxes.
• Unselect "Password and other sign in data" if you do not want to clear your saved passwords.
• Click Clear data.

Safari

• Click Safari in the top left, choose Preferences> Privacy, then "Manage Website Data"