Would you like to watch and listen to a worker spray-cleaning a heat exchanger using controlled liquid nitrogen? Check it out at Conco Systems Inc.'s web site (video link at bottom of page).

The amateur 32-second video makes you feel you're right there with the protective-suited worker as he cleans the top and the tubes of a heat exchanger. Conco, based in Verona, Pa., also has a video on its site that lets you watch and hear the cleaning of air-cooled condensers