Abstract Despite the use of chemical scale inhibitors, fouled layers still form on the tubes in the brine heater and heat recovery sections of M.S.F. plants, necessitating the use of mechanical cleaning. Operating experience with GEA-EST On-line Tube Cleaning Systems in the Gulf Region is presented. The reasons for developing the batch system are outlined. The main features of the system described are reliability, low maintenance and ease of operation. Good ball distribution and avoidance of ball damage are essential requirements, and are fulfilled by this design. The benefits to be gained by the installation of a GEA-EST ball cleaning system in the heat rejection section include not only improved heat transfer but also better corrosion resistance. The need for some form of secondary screening close to the heat rejection section or make-up inlet is emphasized.