Clear Cache Link on the Toolbar
One of the ways to clear cache is clicking on the link which exists on the admin toolbar. By default, only the admin users can see the clear cache button on the toolbar.
Authorities
Although It only appears for admins as default, you can make it visible by user role. This feature allows you to show the clear cache button which exists on the admin toolbar based on user roles.
First you need to open the settings page of wp fastest cache. Then you need to click on the settings link as you can see in the picture below.
Then you can select the roles you want on the popup lighbox.
Hide Toolbar Link
The WP Fastest Cache menu is displayed on the admin toolbar by default. If it bothers you, there are two methods available to help you to remove it easily.
Method 1: Using Filter
You nedd to the filter on your theme’s functions.php file.
add_filter( 'wpfc_hide_toolbar', '__return_true' );
Method 2: Using wp-config.php
You need to add the following line after <?php which exists on the top of wp-config.php file.
define('WPFC_HIDE_TOOLBAR', true);