you dont use any chemicals, the setup is similar to say sand blasting/grit blasting, but the media you use is volcanic ash and heated water and blasted out at a low pressure, the system can literally take the print of a cigarette packet without damaging the packet.
the hydro blasting isnt something you'd want to look at unless you want to pay big bucks, but if you do i could get you a daily price for the use of the machine.