Fill a large, throwaway container with tepid water. Next, take some nail varnish – we used variations of teals and greens – and swill it through the water with a wooden skewer (about 3 large drops of each will do the trick). Immediately dip a plain white mug in and out before the varnish sets. Leave to dry. If you don’t like the pattern, clean with nail varnish remover and start again. To seal, spray with PlastiKote clear sealant spray paint (mugs not suitable for dishwashers).