A device and system are disclosed to clean the interior of tubes in air-cooled heat exchangers. The device is attached at each end of a tube by electromagnetism; either directly to a ferromagnetic tube header, or to a ferromagnetic plate secured to a non-ferromagnetic plug-type header or to a plate-type header of any metal. High pressure air with entrained dry finely-divided abrasive is conducted through a nozzle supported by the device. At the other end of the tube, another device supports a nozzle that captures the air, spent abrasive, and removed material. Spent abrasive and removed material are separated by filtration from the air before the air is exhausted to the environment. Tubes are cleaned to a bright metal condition, suitable for inspection or application of a corrosion-resistant coating, or to a lesser level of cleanliness appropriate for return to service.