Sacramentals are those rites, actions, prayers and objects, either instituted by the Church as a means to obtain for the faithful spiritual and temporal favours from God. The sacramentals benefit the faithful by obtaining actual grace, forgiveness of venial sin, remission of temporal punishment, health of body, material blessings, conversion of hearts, and protection from evil spirits.

These effects depend upon the mercy of God Who regards the prayers of the Church, and upon the dispositions of those who use the sacramentals. The chief sacramentals are the many blessings given by members of the clergy, exorcism, and the blessing and use of such objects of devotion as holy water, candles, medals, rosaries and incense.

In a beautiful little booklet called 'How to Avoid Purgatory', the author tells us:

"Only in Purgatory can one understand ardently the poor souls longing for Holy Water. If we desire to make a host of intercessors for ourselves, let us try to realize now some of their yearnings, and never forget them at the Holy Water font. 

When sprinkling Holy Water for your loved ones, your friends, etc., do not forget the priests, especially those of your own parish, who have served the sacraments and holy masses. In gratitude, you should give them sprinkling of Holy Water several times daily and have Masses offered up for the repose of their souls. 

Sprinkle a few drops of Holy Water and pray fervently: “O God, in Your Mercy multiply these drops into as many drops of Holy Water as there are souls in Purgatory, and allow them not to fear the pains of Purgatory, as long as the moisture of Holy Water is present.”