BBJ Mold Control for HVAC Systems and Air Ducts, control and inhibit the growth of microorganisms – such as gram positive and gram negative bacteria, algae, and mold – in HVAC Systems and Air Ducts. This product is RTU (Ready-To-Use) in a 14 fl. oz. aerosol can; use this product in lieu of BBJ Maintain C-1 Concentrate. Download MSDS