Step 1: On a PC, click the "Firefox" menu in the top left corner. Next, select the right arrow next to "History >", and click "Clear Recent History".
Step 2: Make sure "Details" is expanded, then select "Cache" from the list. Uncheck everything else.
Step3: In the "Time RangetoClear" drop down, select "Everything".
Step 4: Select "Clear Now". Your computer will work for a moment, and the process will be complete. You've successfully cleared Firefox's Cache!
Clearing cache for Firefox 33
Step 1: Click the Menu button ("hamburger button" - the one with three horizontal lines) and then choose Options.
Step 2: Firefox for Mac: On a Mac, choose Preferences from the Firefox menu and then continue as instructed below. With the Options window now open, click the Privacy tab. In the History area, click the clear your recent history link.
Step3: If you wish to clear other kinds of stored data, feel free to check the appropriate boxes. They will be cleared with the cache in the next step.