Maintaining the cleanliness of internal surfaces in the tubes of heat-exchanging equipment is a task directly connected with the operation of such equipment in a corrosive wear of its parts. R&D Institute of Urea has been successfully using Thermoabrasive blasting; Hydromechanical cleaning; High pressure hydrocleaning Vortex blasting cleaning; chemical cleaning (with ortho-phosphoric acid and ultrasonic cleaning for cleaning of scales in heat exchangers. The article gives details of each method used by the institute with specific reference corrosion.