Moonblood

Moonblood: Celestials use this silvery substance as warpaint, painting their faces and other exposed areas of their bodies with elaborately entwined holy runes before entering battle. Proper application of moonblood warpaint takes 1 hour and requires a DC 22 Craft (painting) check; a failed check means no benefits are gained and the moonblood is wasted.
When the moonblood runes are properly applied, the warpaint grants a +2 sacred bonus to Armor Class. The warpaint lasts for 1 day, then is absorbed harmlessly into the skin. An evil creature that touches moonblood takes 1d6 points of damage.
One application of moonblood costs 1,500 gp.

Source: Book of Exalted Deeds