Step 3: Lay down a stripe of latex.
Notice we are touching the skin with the palette knife. When you are happy with the stripe, let it dry. Don't allow the latex to touch itself or else it will stick to itself and you'll have to do it over.
Clean the knife with alcohol or the toner if it's got alcohol in it. Don't use it on the skin again, yet.
Instead, get out the injury stack and, using the clean palette knife, scrape out a very small amount of red, maroon, and eggplant onto the palette. You only need a little bit. Also place a very small amount of baby powder on the palette.
More on cleanliness: a pan of greasepaint might as well be labelled "petri dish". Never dip a brush or sponge directly into anything you're not going to throw away that day, because you'll be transferring all sorts of germy bacterial things into it. Greasepaint is a loving medium perfect for hosting loads of creatures.
On a side note, somewhat related to this: if you currently use a cover-up stick on your zits, and you notice that the more you cover them the worse they get... well, is it a surprise? Use a clean brush or a cotton swab to remove product from your cover-up stick rather than touching it directly to your face to avoid getting zit germs back on your cover-up product. Bluck!
Since I use my paints on multiple people, I have to be very careful about avoiding contamination. In the case of this model (my daughter), I happen to know that she has recently recovered from a fungal infection of the hands. However, if I didn't know that and wasn't using appropriate precautions, my greasepaints would now harbor that fungal infection and pass it to everyone I used it on from here on out.
Since it takes a while to incubate, it could be weeks before an actor who got their eye blacked from my handiwork developed itchy scaly weepy skin around their eyes, and longer still before it was recognized as a fungal infection, and even longer before the treatment was over. That could ruin the actor's chance of working, and potentially contaminate other actors if the next makeup artist was slackerly. If it could be traced back to my mishandling of materials, I could be sued. So I'm extremely careful about making sure my products stay as pure as they can.
By assuming that everyone has some evil communicable disease, it's not hard to be in the habit of avoiding contamination.
Is the latex dry yet? Great! Make sure the lids are on all your products and let's move on.