Sword Cleaning

Sword Cleaning was a practice considered important throughout much of Narnia's history.

Its necessity was first revealed shortly after the Battle of Aslan's Camp. After slaying the wolf Maugrim, Peter did not wipe the blood off of his sword. Aslan told pointed out to Peter that he had left his sword dirty, and instructed him to always clean his sword.

Another instance occured far later during the Calormene Conquest. Eustace fought two Calormene soldiers to liberate some dwarfs. The following morning, Tirian found out that Eustace had put his sword away still covered in blood, thus creating a mess.  Eustace was reprimanded.