Many people are surprised to learn that porcupines are good to eat. Like many rodents, they eat vegetation, and become well fattened on this food. However, if you are going to eat one, a natural question that may spring to mind is how do you clean the porcupine? Saying, "Very carefully" is sage advice, but not particularly helpful.
The biggest worry is the quills. However, the belly of the porcupine has no quills. The first step is then to roll the dead porcupine over on its back, to expose the belly. Using a sharp knife, make an incision just above the genitals or vent. Take care to cut just under the skin and not to yet puncture the membrane covering the abdominal cavity.
With the knife blade just under the skin, cut in a line up to the neck of the porcupine. Also cut the skin from the central incision to all four feet, ending at what would correspond to the ankle or wrist bone. It now becomes a little trickier.
Very carefully, to avoid the quills, cut all the way around each wrist or ankle, and around the neck. Slowly and patiently, curl the skin back, rolling it so it becomes inside out. The hide helps to protect against the quills, so you are really rolling the quills away from you. The skin can be curled this way because there is a layer of fatty tissue just under the skin that releases from the skin if you use a steady pressure.
What you finish with is the porcupine properly skinned. The hardest part is over. Cut off the four feet and the head, and you are left with a carcass without spines to stick you.
At this point, cut carefully through the membrane protecting the abdominal cavity. Don't puncture the intestines, however cut deep enough that you can slit the membrane all the way to the rib cage. Also, cut around the genitals and anus. You should then be able to reach in and pull out all of the entrails, making sure you also get the entire windpipe to prevent a gamy taste.
Rinse the carcass well, to remove any blood, portions that didn't come out cleanly, or particles of dirt. At this point, the porcupine is ready for cooking, but you aren't quite done. It can be easily quartered, however if you plan on frying it, the fat needs to be carefully cut from the body. This isn't vital if you are planning on cooking the porcupine in a stew, since the fat adds greatly to the flavor of the soup stock. When frying, the fat can even be retained for a good stock for soups and stews.
Note that the fat is thick and sweet, rather like pork, which also means that it needs to be used quickly or otherwise frozen, to prevent spoilage. In addition, older animals tend to have tougher flesh than younger ones, so this can be a consideration for how the meat is going to be prepared.
If you do get a few quills in your skin, don't panic and don't just yank them out. Each quill is hollow and has a slight vacuum that causes very tiny barbs to stick out. If you snip the base end off the quill, the vacuum is released letting the barbs lay down. They then become much easier to pull out.
There you have it, how to clean a porcupine. The flavor of the meat is great, and once the quills are no longer an issue, the porcupine isn't a lot different for the cleaning than is a rabbit.