Cursed Water. This is a variant of holly water that is specifically formulated for those who carry demonic blood/spirits. 
To do this you need jalapeno oil/extract, sulfur powder, and water. You simply bring the water to a boil and add the sulfur, jalapeno oil to the water. And then you say your “curse” or “blessing”. The more heart felt the better. You then let the water cool, and fill the viles. 
While Cursed Water is often used in darker magic, it is primary use is has holly water for those that can't easily handle “Normal” holly water. May this prove of value.