From today's Column 8 in SMH:

It's great to hear that the youth of Australia are investing time and energy in R&D. Jane Salmon-Donovan, of Lindfield, reports on the latest breakthrough, "A recipe for varnish remover" devised by Lindsay Donovan, aged four. "Mix all your Play-Doh colours together to get a uniform khaki. Add orange juice. Yoghurt is optional. Drive your toy car through the mixture on a varnished table for half an hour. Also works for paint."