chiburi

Also called Chiburui, usually written 血振 in Japanese, literally means “shaking off blood,” is the act of removing blood from the katana before sheathing it. This is done to keep the blade from getting rusted and dirty.
It is most commonly done by flicking the sword to shake off the blood, or using a dedicated white piece of cloth/paper to wipe it off.
The elbow crease wipe, albeit considered a crude act, can be used as a last resort (it looks badass though so ironically it is depicted more often).