Hex Bag
A hex bag is a charm composed of a mixture of herbs, talismans, other supernatural ingredients placed in a piece of cloth and bound with leather. It is used to bring about a specific effect, usually, but not always, malicious. A hex bag intended to harm someone also contains a personal belonging of the intended victim (usually clothing).
Apparently the only ways to stop a hex bag are to find and burn it, have the witch casting the spell break it, or have a powerful counter-spell cast. When a hex bag is burned the flames become a bright blue.
Appearences
3.09 Malleus Maleficarum
Hex bags are made by a witch, Amanda, and a demon, Tammi, in order to kill people. These hex bags contained rabbit's teeth and bird bones. One hex bag is intended to kill Dean. Sam is unable to find it, but Ruby arrives with a potion that saves Dean.
4.07 It's the Great Pumpkin, Sam Winchester
Hex bags are used to kill several ritual sacrifices. The bag is made from a Samhain talisman, gold thread (an extinct plant), and the charred metacarpal bone of a newborn baby. One of the hex bags is placed in the wall of Sam and Dean's hotel room. It is found by Castiel and Uriel, who appear to have neutralized it by the time Sam and Dean arrive.
After the ritual requiring the sacrifices is completed, Samhain is raised, breaking one of The 66 Seals.
4.10 Heaven and Hell
Ruby makes a hex bag that shields Sam, Dean, Anna, and herself from demons, specifically Alastair, and angels. Ruby later burns one of them to reveal herself to Alastair and make a deal with him as part of a trap devised by Sam.
4.18 The Monster at the End of This Book
Dean and Sam have multiple hex bags to keep Lilith from finding them, but Sam burns them in order to have the opportunity to confront Lilith.
5.01 Sympathy for the Devil
Sam makes hex bags to keep the demons from finding them. When Dean asks where Sam got them, he reveals that Ruby taught him how to make them. Later in the episode, Castiel reveals the hex bags cannot prevent Lucifer from finding them. He marks Sam and Dean with Enochian Sigils to hide them from angels.
5.20 The Devil You Know
Crowley reveals that he used a Magical Coin hidden in the Impala to track and eavesdrop on Sam and Dean. The coin worked in spite of their hex bags.
8.14 Trial and Error
Sam and Dean plan to make a hex bag to protect Ellie from being detected by Crowley so she can dodge her deal.
8.22 Clip Show
When Crowley threatens to kills Sarah Blake, Dean and Sam arrive to protect her. While Dean demon proofs the place, Sam catches up with Sarah and finds out that she is married and has a daughter. Crowley calls a few seconds before the deadline and starts to count down to Sarah's planned death which prompts the boys and Sarah to arm themselves and readily wait for Crowley to appear. After Crowley finishes, Sarah suddenly collapses and starts to choke to death. Sam realizing that Crowley is using a spell that involves a Hexbag starts to hurriedly search for it but to no avail. Sarah then dies and Dean in anger chucks the phone against a wall which breaks apart and shows that the hexbag was in the phone all along.
Supernatural: Bobby Singer's Guide to Hunting
In this tie-in book, it is stated that the hex bags used to shield against demons and angels contain two bones from a chicken's foot, an unbroken spider egg, equal quantities of lavender and hemp, and goofer dust.
