While fabric dye is the best dye type for tie-dying shirts, but you can also do it with food colouring. Unfortunately, cotton shirts will not hold food colouring well, so always use shirts made from wool, silk or a synthetic fabric. These can be expensive, so look at your local charity ships for cheap garments to jazz up with colours.
Gather the shirt at the collar and twist the fabric. Place a few rubber bands on the shirt to secure the twist.
Add the vinegar to the large bowl and fill the bowl with water. Place the shirt in the bowl and let it soak for 30 minutes. Pick out what colours you would like to use for your shirt.
Empty the water mixture from the bowl but leave the wet shirt in the bowl. Drip the selected food colours on to the shirt. The water in the fabric will help distribute the colour.
Place the bowl in a microwave and heat for about a 30 seconds. Allow the shirt to cool, and then rise the shirt in cool water.
Remove the rubber bands and allow the dyed shirt to air dry. Once the shirt is dry it is ready to be worn!
Combine this tie-dye technique with other DIY shirt projects, like creating a halter top out of your tie-dyed shirt to create a fun and original item.