Here is the Roman Catholic blessing of candles via exorcism. This is a nice standard exorcism you can do over any candles you use for ritual purpose.
℣. Our help is in the + name of the Lord.
℟. Who made heaven and earth.
℣. The Lord be with you.
℟. And with your spirit.
℣. O candles, I exorcise you in the name of God ✞ the Father Almighty, in the name of Jesus ✞Christ his Son, our Lord, and in the name of the Holy ✞ Spirit. May God uproot and cast out from these objects, all power of the devil, all attacks of the unclean spirit, and all deceptions of Satan, so that they may bring health of mind and body to all who use them. We ask this through the power of our Lord Jesus Christ, who is coming to judge both the living and the dead and the world by fire.
℟. Amen.
℣. Let us pray.
Lord Jesus Christ, Son of the living God, light of everlasting life, you have given us candles to dispel the darkness. We humbly implore you now to bless ✞ these candles at our lowly request, and hallow ✞ them by the light of your grace. By the power of the Holy ✞ Cross, endow them with a heavenly blessing. May the blessing they receive be so powerful that, wherever they are placed or lighted, the princes of darkness shall flee in fear, along with all their legions, and never more dare to disturb those who serve you, the almighty God. Let the entire building in which these candles are kept, be free from the power of the adversary, and be defended from the snares of the enemy. Grant we pray, that those who will use these candles may be protected from every assault of the evil spirit, and be safeguarded from all danger. Through Christ our Lord.
℟. Amen.
They are sprinkled with holy water.
Roman Ritual Book of Blessings