Mix 1/4 cup (60 ml) boiling water, 1 teaspoon (5 ml) vinegar, 1/8 teaspoon (1/2 ml) oil and 4 to 8 drops food colour in shallow bowl. Repeat if second colour is desired. Make sure to agitate mixture with fork or small whisk so oil droplets are small. Gently roll egg in one colour for 30 seconds or until the egg is the desired shade. Transfer the egg to second colour and repeat the process. Use a slotted spoon, wire egg holder or tongs to add and remove eggs from dye. Allow eggs to dry. Wipe away excess oil with a paper towel.