Surgical Spirit (from the chemist)
Put your fabric over the jam jar and secure with the elastic band. Using your pen draw a pattern on the fabric.
Circles work best, but any pattern will do. Leave a gap between the lines for the colour to bleed.
Take a syringe and fill with surgical spirit and then drop in to the centre of the fabric.
Move the fabric to a blank area and repeat as required.
I washed the fabric after we dyed it and some of the colour did come out, but not much and then I heat set it with a hot iron.