Crisps or salted crisps

The decision in the 50s was whether or not to add salt to one's crisps. Flavoured crisps didn't exist. Lurking in the depths of the Smiths crisps packet was a little blue twist of paper with salt in it - you poured in the salt and, hand over opening, shook the packet. Smiths crisps was something that walkers might take with them as a snack.