What is the best at home treatment for psoriasis?

Tanning bed: Because you said "home treatment". Obviously there are a number of topical creams (related to retin-a, corticosteroids, coal tar, and vitamin d -- for instance). As far as home remedies: tanning is favored, but only insofar as to avoid sunburning. If you overdue the tanning bed you can run the risk of skin leathering or skin cancer, but skin was "invented" anticipating regular sun exposure.