Leave the task to the professional. This thick gel cuts through standing water and works triple duty to dissolve tough clogs, prevent new ones from forming, and remove unpleasant odors. Our gas engineers carry a gas safe register id card with their own unique licence number, showing the type of gas work they are qualified to do before any gas work is carried out. Nice hub i never new cola could be used to unclogged drains i have one that gets clogged every now and then will give these a try. Water.