For ages, warriors have collected body parts of those they have killed. These trophies have been used as currency, as well as bragging rights. The most common purpose of taking a trophy from a victim though is for proof that a contract has been met and many hunters use this method, as hauling dead bodies around can quickly become impractical. Out of all the items that can be cut off of the body, the ear has proven time and time again to be the easiest and has become the most common to collect among mercenaries, pirates and bounty hunters.
On species that have an ear, the most effective way to separate the ear is to grab the tip of the top ridge and start from the back with a bladed weapon, following through until it has been fully parted from the side of the head. However, certain species' ears are a bit harder to find and remove.
After the trophy has been acquired and the bounty collected, many will keep it for display, often in a trophy room with holoimages of their victims. Some will fashion them into a necklace or as a decoration for their armor. Some will even carry them around in their tool belts to use in a pazaak game. The choice of display method varies by owner, but the intention to impress or intimidate is always the same.