code: public static function remove($strKey)
  	{
  		$objConfig = static::getInstance();
  
  		if (strncmp($strKey, '$GLOBALS', 8) !== 0)
  		{
  			$strKey = "\$GLOBALS['TL_CONFIG']['$strKey']";
  		}
  
  		$objConfig->delete($strKey);
  	}
docs: Permanently remove a configuration value
  
  @param string $strKey The short key or full variable name