I'm not sure I understand your question. Is the stencil made of baby powder, or do you want to wipe it off with baby powder?
It's a textured stencil, you'll have to scrape and sand it off.
What are you stenciling on and what you you used to stencil? Answering your question with some good solutions needs a bit more information. You may be able to wipe off a freshly done stencil with a kitchen sponge that has a rough side.
Hello there Joyce, I would rub it down or sand it off.