How to Clean the Cache on a Mac
Your Mac web browser saves pages you open in a "cache." This improves the loading time of websites you visit regularly, because the browser can access the information in the cache instead of downloading the information again. However, you may need to clean the cache in order to ensure privacy on a shared computer, to view updated information on a page. Additionally, if you go for a long time without cleaning your cache, it can slow down browser speed by using too much memory.
Go to the "Applications" folder and double-click the "Safari" icon.
Click the "Safari" menu and scroll down to "Empty Cache."
Press the "Empty" button to clean out the cache.
Go to the "Applications" folder and double-click the "Firefox" icon.
Click the "Firefox" menu and scroll down to "Preferences."
Click the panel labeled "Advanced" along the top of the window. Press the tab marked "Network."
Press the "Clear Now" button in the "Offline Storage" portion of the window.
Press the red button in the upper-left corner of the window to close it.