I heard about this, and researched it on the internet. I have used it several times now, and love it. Apparently the aspirin has salicylic acid which works like a gentle acid peel, removing dead skin, tightening skin, shrinking pores, helping with acne & facial warts. This treatment makes your skin noticeably softer, fresh & radiant. One "recipe" for this that I found suggested adding jojoba oil to help it "stick" & not be so powdery, but I found it harder to remove & also I read that moisturizing right after would affect the action of the salicylic acid, so I assume adding oil to it might do the same, so after the first time I omitted it, consequently I wait to moisturize by a few hours, or the next day. If you have very dry skin, you may want to go ahead and moisturize right after, although I have not found this to be drying to my skin. I do this before showering as it's much easier to remove in the shower. The mixture is very powdery as it dries, so be ready to hop in the shower once it starts falling off & flying around (you'll see what I mean) to avoid getting it in your nose & eyes. I apply it to my neck, chest & both hands (including the backs) as well as my face.
**Also, use your best judgment if you have sensitive skin when you decide to try this, it's always a good idea to test a small area when you try anything new & see how you'll react before you cover your face in it.