The invention provides a method for increasing rainout from an autorefrigerated vaporous cloud containing hydrofluoric acid formed from the escape of hydrofluoric acid from its containment facility comprising admixing from about 50 to about 80 weight percent hydrofluoric acid with from about 20 to about 50 weight percent of at least one selected from the group consisting of a sulfone having the formula R-SO 2 -R', wherein R and R' are the same or are different, and are selected from the group consisting of halides, alkyl groups, aromatic groups, alkylhalide groups, or arylhalide groups containing from about 1 to about 20 carbon atoms and a sulfone having the formula R-SO 2 , wherein R is a bidentate alkyl group, an aromatic group, an alkylhalide group, or an arylhalide group containing from about 1 to about 20 carbon atoms.