OneCall™ Ventilation also offers specials that work with customer's individual needs. Our maintenance Services specials, said OneCall's owner, completely restructures a cleaning process according a client's needs. The Emergency Cleaning division has staff working directly with the client to clean and repair hoods and fans in order to ensure a client's success. Employees will even take a client's instructions, provided those instructions are within the constraints of the law and good public health policies and established guidelines.