Can your holy water remove this stain?

Author's Notes: I'm launching a day early due to time constraints. The best season is upon us now, right at this very moment. AMC Fearfest is in full effect. My house is completely haunted out. It's a good time to be alive. From October 1st - 31st, I try to watch as many horror films as possible. Last year, I finally got to see the much acclaimed "The Exorcist." (What a ride.) So, I got to thinking: what if you were convinced your friend was possessed, but you didn't have any holy water? Now, what if you were Grim?