Сlean your cache in the browser regularly.

Google Chrome:
Tools - Options - Advanced - Clear Browsing Data - Select the data you want to delete - Clear Browsing Data.

Safari:
   +     +    or follow the instruction below:
From your Safari menu bar click Safari - Preferences then select the Advanced tab - Select Show Develop menu in menu bar - Now from the menu bar click Develop > Empty Caches.

Opera:
Tools tab - Settings - Advanced In the left menu History - Press Clear, clean history and cache on the left in Cookies menu - Select Managing cookies and delete all that is showing (there is a Delete button).

Mozilla Firefox:
Open the Mozilla Firefox and click on Tools menu - Select Settings - Advanced - Network - Independent store (in the Mozilla Firefox 2 Cache section) - Click Clear Now - To save the settings, click OK and close the dialog box.

Internet Explorer:
Find Internet Options (usually found under the Tools Menu but can be found in different places depending on which version you have) - General - Clean History (History of views), Temporary files (Temporary Internet Files) and Cookies. In IE8 this can be done with one click on the Delete button, in earlier versions each item must be removed separately.