I made this for my sister.
To make this t-shirt I used De Colourant Mist (i got it in Art Van Go, at the Knitting and Stitching show in the RDS in the Autumn. If you are not an Irish person who likes crafts, you will probably have no idea what on earth that is. i looked it up and found a place that sells it for thirteen dollars here: http://www.uniquestitching.com.au/p/1193990/decolourant-mist–a-fabulous-bleaching-agent-without-additional-colour-the-effect-of-the-mist-is-fantastic.html)
i made a stencil out of freezer paper first (it says warpaint, which is the name of my favourite band), and then i just hung it up on a line and went crazy with a spray bottle full of the de colourant. (i had to transfer the liquid to a better spray bottle, as the one it came in let out big drops, which was not really the effect i was looking for.)