Iknow its an old thread, came across it from google. Just a heads up for anyone that reads this I been using some dope shit i found on Amazon by searching "graffiti etch", no having to handel or worry about the chemicals already comes in a mop and everything

http://www.amazon.com/Etching-Solution-Crafts-Graffiti-Marker/dp/B00N6W6V4I/ref=sr_1_1?ie=UTF8&qid=1409642935&sr=8-1&keywords=graffiti+etch