[sdiy] Hydrofloric Acid ***WARNING***

[Mike I.]

HF destroys nerves under the skin very rapidly, effectively 
anaesthetizing the exposed area as it destroys skin and tissue - if you 
get a drop on your skin, you may not even notice it, until after the 
damage is done. Much worse than sulfuric, nitric or hydrochloric acid.

Ammonium Bifluoride solution can also be used to etch glass or quartz. 
It is not quite as dangerous as hydrofluoric acid, is slower-acting, but 
still requires very careful handling to ensure safety.
Mike