Chekov's Spell -- This spell has a two-fold effect. The first is to make the target item almost-unnoticeable to anyone not specifically looking for it. The second is that someone who has seen the item will remember it when they encounter a situation that would be perfectly solved by use of said item.
During big fights in the arena or gladitorial ring between two well known or important warriors. When one looses and dies, the crowd throws copper coins into the arena for the slain warrior to take with them on their passage of death. This is to make their passage and afterlife richer and less troubled. It is a sign of respect.