Their expertise is to clean a crime scene after the pedophilic activity of a Catholic priest and presumably dispose of any evidence. They utilize standard cleaning equipment but also use a backpack machine called the "Kumby" and a mower-esque cleaner called the "Kumboni", which is a reference to Daniele Comboni. All members were run over and killed by Father Maxi after they offered him a fine life away from town but implying his replacement would be a sexual predator.
After assuming Maxi was on a debaucherous and criminal molestation rampage, they cleaned the South Park Church, Stan's house and the Kidzone Roller Rink. They have a van containing their cleaning equipment but it was also used to lure Butters and lure or kidnap Stan and Clyde to set a trap for Maxi.