Refrigeration drain unblocker. DrainSafe is a powerful drain unblocker for use on refrigeration systems. It has been designed to quickly dissolve slime and biofilms. These buildups are commonly found in the condensate lines draining away from chilled storage and dairy cabinets and can cause blockages and the spread of bacteria. Featuring an industrial strength formula, DrainSafe is acceptable for use on drains in and around food processing areas.