There used to be a product that help in blood trailing called STARLIGHT BLOODHOUND, when you used it you sprayed a and turned off your light and it would glow when it made contact with any sort of blood trail. I know of a cheap way of making your own that doesn't glow (Hydrogen Peroxide 3%), it just foams when it makes contact, but I really would like to find where I could get it. If anyone knows comment back to me, thanks!