There is also a chemical being promoted for stencil application.

Just put a photocopy face down on the skin, apply the liquid to the back of the paper and the stencil comes off on the skin and stays. No need for thermal copies anymore.

It works by liquefying, dissolving the toner and it is absorbed into the skin, not just on it.
Traditional thermal copy paper contains caruba wax and crystalline violet which sits on the surface and is hardly absorbed (much to our dis-pleasure when it rubs off).

The chemical is of a type used to dissolve toner inks for clean up.
We rejected this chemical when it was offered and coming in from Canada.
Years ago this cleaner used to be routinely available to service personnel but was
subsequently limited to small bottles because of toxicity problems.

If you breathe the fumes you will likely feel disoriented and woozy for hours.
This reaction may be the least of the medical problems to be expected.