The right shampoo can get you on your way. Use one that has salicylic acid, the active ingredient in aspirin. It causes peeling, which is just what you want to loosen up the scales. Other helpful ingredients to look for are lactic acid, urea, tar, and phenol.
Another way to get the job done: Put oil on your scalp. Not the stuff that goes in your car, but the kind you eat. Vegetable, coconut, or olive -- they all help get those scales off.
You can also check the drugstore for a liquid that's a mixture of mineral oil, glycerin, and phenol, says Charles L.G. Halasz, MD. If you can’t find it there, look online.
Whether you go for the oil or the liquid, the important thing is to put it on your head and leave it there for 30 to 60 minutes.
If you have thick scales, Halasz suggests a few other ways to boost the oil's scale-busting power once it’s on your scalp:
Wrap a hot, moist towel around your head, turban-style. Leave it on for about 20 minutes.
Put on a shower cap (to protect your pillows and sheets) and wear it all night as you sleep.
Next comes a shampoo and comb-out. Use a fine-toothed comb, and be gentle, Halasz says. If you're rough and scratch your head, it will make your psoriasis worse. "One of the worst things you can do is pick flakes out with pressure, such as with your fingernails or a comb."