Nestle's Creamola Foam Crystals were available to buy in the 1950s to 1998, when production from its Glaswegian factory ceased. They were a kind of powder that you added to water to make a foamy, refreshing drink. From memory it was available in a couple of flavours incuding raspberry, lemon and orange, then later on cola. It came in a tin and all you had to do was dissolve the soluble crystals in water for a colourful, fizzy drink.
Currently, there are a number of online petitions running to try to bring back Creamola Foam. Good luck to them!