The gunge used on kids TV shows, like Dick & Dom…, needs to be non-toxic, brightly coloured and sticky. There are lots of long chain polymers that can be used to make gunge, but in the UK, the most common recipe is water and powder paint, thickened with hydroxycellulose, which is plant-based and sold as Natrosol. In the US, methylcellulose is used (although, it can have laxative properties, so try not to get too much goo in your mouth). Methylcellulose is also used in wallpaper paste (but actual wallpaper paste contains fungicide, so don’t use that if you’re making gunge at home).