The following official prayer from the Roman Ritual may be used by a priest to bless Sacramental salt:
“Almighty God, we ask you to bless this salt,
as once you blessed the salt scattered over the water by the prophet Elisha.
Wherever this salt (and water) is sprinkled,
drive away the power of evil,
and protect us always by the presence of your Holy Spirit.
Grant this through Christ our Lord.