The Corleonesi created a torture chamber in Palermo where torture and get rid of the bodies with the acid. The old style mafiosi should not compete with this madness. Giuseppe Greco aka Scarpuzzedra (little shoe) used those torture chamber and was the best killer for Riina that at some point was afraid of his charisma (Riina never had a bit of it) among the other killer and ordered to kill him with the lupara bianca.