All praise is due to Allah, and may peace and blessings be upon the Messenger of Allah.
The ruling on fumigation varies according to how it is used:
If incense is used alongside talismans, unknown mutterings, or in the manner of sorcerers and soothsayers, it is impermissible to use it or seek treatment through it.
If incense is made from permissible materials, without believing that it possesses power in itself or assigning it to unlawful rituals, there is nothing wrong with using it, provided its benefit has been established through experience and it does not involve anything prohibited by Islamic law.
The virtue of black seed is established in the Sunnah, and it can be used in several ways. Fumigating with it may be beneficial if its effectiveness is established medically or through reliable experience.
It is permissible to fumigate a person, their clothes, or their home. However, Islamic teachings do not specify a particular time for fumigation, and there is no evidence that fumigating with coarse salt and black seed is a guaranteed treatment for magic, envy, or the evil eye.
In conclusion, it is permissible to use incense made from lawful materials if its benefit has been established, provided it is free from talismans, shirk, and prohibited practices, and without believing that it has independent supernatural effects.
And Allah knows best.