Note: Please, please, please know that I don't condone animal cruelty of any kind, and I do not support animal sacrifice! I cannot stress that enough. Parts should be obtained humanely either from local butcher shops or during hunting season. I work closely with the land and its animals and spirits and when hunting animals for food, we let no parts go to waste.
Antlers can be used in place of wands. Their rhythmic clanking and drumming can be used to help generate energy for spell and ritual work, as well as attract spirits to our sacred space. Deer are drawn to the sound of antlers clanking, especially during rutting season. Likewise, their spirits are also drawn to the sound.
The rhythmic sounds they make can also be used to lul you into a trancelike state when working with etheric journeys or connecting to the spirit world.
Feathers can be use to clear away energy or to connect to the avian from which they were taken. If you want to work with air elementals, you can also use feathers and whistles to attract them to your workspace.
Shells can be used to connect to the water element and oceanic energies. Placing water in a seashell on a full moon and gazing into it can also be used as a means of divination.
Claws and teeth can tear and rend, but they can also protect. Bless and wear them as amulets of protection or use them in rituals and spells to tear at the image of your enemy or to pierce a poppet made in their image.
Wasps and Spiders
Wasps and Spiders can be added to curse jars to bite and sting your enemies.
Spider webs can be added to binding spells to tie up and hold enemies working against you.
I personally use bones and and other such related materials to connect to certain energies or spirits when doing magical/ritual workings. I've also heard of bones used for housing spirits and thoughtforms.
For example, I've a relative that uses a deer skull as a housing vessel for a familiar spirit. Skulls are wonderful for spirit housing and can be cleansed and prayed over to invite familiar and totem spirits to your space.
Bones can be a direct connection to the spirit of the animal from which they are taken. If the spirit of the animal (the owner of the bones) does not wish to work with you, you can invite another similar spirit (one of the same species) to reside in the spirit vessel.
To entice a spirit into the bone vessel, you need to cleanse it and prepare it as a house for the spirit. I personally bleach by bones with a 25, 25, 50 mixture. 25% peroxide, 25% bleach, and 50% water. So, if I do 1 cup of peroxide and 1 cup of bleach, I would use 2 cups of water, as an example.
Once the bones are bleached and cleaned, you can them allow them to dry. Soak them in salt water, wipe them off, and allow them to once again dry. Then, anoint them with an oil of your choice (I usually use cedar or sandalwood, just as a personal preference.) Then I pray and chant over the the bones (usually a skull) and ask the spirit to join me and work with me as a guide.
I have a special altar upon which the bones are placed and to it I add candles and herbs associated with the spirit. For example, if I were using a deer skull, I would have cedar wood candles, acorns, dried grass pods, and other items that the creature enjoyed in life.It can take time for the spirit to come and reside in the vessel, but you will know once they do.
Also, always remember to show respect to the animal from which the bones were obtained, and always obtain them humanely. Leave an offering for the animal as a show of appreciation and thank them for the bones you have collected.