CAUSTIC SODA is white hygroscopic crystalline powder and readily absorbs water from the air, so it should be stored in an airtight container. It is very soluble in water with liberation of heat.
Sodium hydroxide is frequently used as a cleaning agent where it is often called “caustic”. It is added to water, heated, and then used to clean the process equipment, tanks, drains, etc. It can dissolve grease, oils, fats and protein based deposits. A sodium hydroxide solution will leave a yellow stain on fabric and paper.
Concentration is varied according to water conditions, temperature and type of cleaning requirement with higher concentration used for better performance and hard stains.