From Protector of the Grey House:
Natalia didn’t head for her mom’s house right away, but went to the corner market first. She bought a water pistol, and two small empty jars with cork stoppers. She went to the Catholic Church up the street and filled the jars and water pistol with holy water. She read that holy water affected younger vampires, and hoped Donald wasn’t ancient. There was a table filled with candles and wooden crosses. She took a wooden cross and stuffed some money in the donation box, not sure if a cross would work. Her research wasn’t too clear on holy symbols and their effect on vampires. She stuffed the jars in her pocket and made sure the paring knife she took earlier had not fallen out of her jacket pocket. If she were wrong about Donald and he was just some asshole human, a knife would be more effective than the holy items.