I haven't done tie dye since I was at school and I had a plain t-shirt that I had previously spilled on that was crying out for some more random splodges.
Tie dye is really simple but very difficult to control the pattern completely so it's kind of therapeutic. I did some folding and rolling and tied with elastic bands. Then i dropped the colour around the bands. I then added another colour and did the same. I let it drye and then washed it to seal.
Hey presto! Stains hidden!