As ricenot recently noticed, the alpha channel on Wick's first person gloves seems to indicate that there were supposed to be stains on his gloves at some point. His guess was that they were meant to be blood stains, however, I don't feel like blood stains would be accurate given how Wick is a man whose wife has since died.
As such, you can probably guess what this mod does. Put it in mod_overrides.