Not something I'm interested in really, but I've seen different opinions of people doing them. Are they a closed practice because of their roots in hoodoo?
Ah, I'm just confused as some sites and responses like this one- https://www.reddit.com/r/WitchesVsPatriarchy/comments/hbthaq/sour_jarshoney_jars/ say that it's closed practice, as do some people on the internet. So are honey and sour jars fine to make? It's confusing as it seems to be rather controversial.
Unfortunately, individuals like to send personal opinions out as fact, and there are people out there who like to take control and tell others what they can and can't do so they can feel righteous and have a soap-box to yell from.
Voodoo is a faith and practice with steps of learning and initiation, so in a sense it is closed because you can't just call yourself a part of that path without being initiated. It would be like telling people you are a doctor without having gone to school. Less a lack of permission, more a lack of qualification
Correct me if I am wrong, but I believe that just about anyone can learn Voodoo practices and become an initiate, as long as they can meet with a proper teacher.
Hoodoo I am less familiar with, but I would assume the same. If in doubt, get to be a part of the community. Enter in at the ground floor and learn how you can become ordained/initiated under someone already on the path.
As for specific workings, like a honey jar, urine jar, sour jar, freezer spells, etc... those ideas are all based on principles shared between many Faith's and practices. Particularly, the magical power of symbolism which is a pretty universal application. Using a jar and filling it with stuff does not immediately make it voodoo/hoodoo. No more than making an altar and praying to a personal deity makes you wiccan.
Take your inspirations, understand where they come from, learn the meanings behind the symbols, then build your own process. Where the line lies, is that you should not then take what you have created on your own, label it's being voodoo/hoodoo, and sell it off. If you want to teach another person what you did, just be sure you explain where your inspiration came from so it isunderstood you used ideas, but created your own thing.
Think of it as citing sources in academic writing. Share your idea but also share its roots and how it differs.