public function clearExpired() {

		$files = glob(Path :: get('cache-shared') . '*');
		
		if(true === is_array($files) && count($files) > 0) {

			foreach($files as $file) {
			  	
			  	$file 		= new File($file);
				$expiration = $this -> extractExpiration($file);

				if($expiration -> time <= time()) {
					$file -> delete();
				}
			}
		}
		
		return $this;
	}