The crews cleaning Britain's railway carriages after they have been used by hundreds of thousands of passengers. Plus, the monumental heroes giving the last resting places of the dearly departed a deep clean. Beware the dreaded black spot.

This time, a giant greenhouse is de-gunked by a team of specialist cleaners, a mansion driveway is transformed by a jet wash duo and we meet a man who is not coy about pond cleaning.

A forest of weeds in Chingford, Essex has consumed a back garden, leaving cleaners to rely on jet washing to clear the debris. A pro cleaner takes on filthy swimming pools full of algae. A giant filthy forklift is cleaned.

This time we meet the jet-set cleaners who clean planes, Birmingham's finest roll out their secret weapon in the battle with the grime and at the toy hospital we learn how everything from dolls to teddy bears are expertly cleaned.

Two professionals take on a job of divine importance as they clean a historic church's filthy entrance, a father-and-son team battle a carpet of moss on a house roof in Hertfordshire. A zoo's penguin enclosure is due a good clean.