I have reasonably bad scalp psoriasis, and i also have it on my ears, shoulders, my face and somewhere else that shall remain private.
I was prescribed coal tar shampoo, dovonex lotion and a topical steroid called locoid for my scalp. I also have dovobet ointment and a coal tar lotion for my other bits.
I used to use the coal tar shampoo and lotion, and the dovonex lotion daily, and keep the dovobet and the steroid for difficult to shift areas.
However, for the past year i have not been treating it at all, I've just been letting it grow and itching it. I know this probably sounds gross but i don't really have a problem with it. I suppose I'm lucky in that most of my psoriasis is hidden from view.
I also have another illness exacerbated by stress (schziophrenia), so annoyingly whenever I am seriously ill with that, my psoriasis flares up out of control and I become all itchy and flaky to boot.
The doctors do try to encourage me to treat my psoriasis. When i was in the hospital, a junior doctor even prescribed me some ointment for it, and that was handed to me along with my pills. But bah, blot knows best.
I gather from the way you write that simply trying to ignore your psoriasis isn't an option. In that case i wish you the best of luck in trying to clear it up.