The /clearcache page is used to clear site data, such as products, categories, and navigation menus. For those using a custom skin, the /flushcache page clears skin data, like that controlled by the layout.txt file. Simply add /clearcache or /flushcache to the end of the url for your site to see these pages.
If your website domain/url were "websitename.com", to instantly see recent changes made to products, categories, and navigation menus you would go to the websitename.com/clearcache page and click the button . If your website were "example.com", you would use example.com/clearcache instead.
In the same example, to see recent changes made to the skin you would go to the websitename.com/flushcache page and click the button.