Similar to the cache in your web browser, your Flash Player may also store data from visited websites locally on your computer. This data is called Local Shared objects (LSO), local storage or commonly “Flash Cookies“. Clearing your Flash Cookies may be useful when you encounter a technical issue with your Flash Player plugin. To clear your local storage (Flash Cookies):
This will clear your Flash Storage across all browsers on your computer, except for Google Chrome. Please perform these steps separately in Google Chrome as it uses a different Flash Plugin than the other browsers.
FarmVille Game GUIDE