protected function _clearDir($type = null, $timeNow = null) {
		switch (mb_strtolower($type)) {
			case 'export':
				$clearPath = $this->_getExportDir();
				$storageTime = $this->_getStorageTimeExport();
				break;
			case 'preview':
				$clearPath = $this->_getPreviewDir();
				$storageTime = $this->_getStorageTimePreview();
				break;
			default:
				return false;
		}

		$result = true;
		$oFolder = new Folder($clearPath, true);
		$exportFiles = $oFolder->find('.*', false);
		if (empty($exportFiles)) {
			return $result;
		}

		if (!empty($timeNow)) {
			$timeNow = (int)$timeNow;
		} else {
			$timeNow = time();
		}

		$exportFilesPath = $oFolder->pwd();
		foreach ($exportFiles as $exportFile) {
			$oFile = new File($exportFilesPath . DS . $exportFile);
			$lastChangeTime = $oFile->lastChange();
			if ($lastChangeTime === false) {
				continue;
			}

			if (($timeNow - $lastChangeTime) > $storageTime) {
				if (!$oFile->delete()) {
					$result = false;
				}
			}
		}

		return true;
	}