I remember those crisps with the separate packet of salt in, from when I was younger. My mum always used to theorise that they were for people who were trying to cut down on their salt intake, so that they could choose how much or how little salt to put on them.

Of course, without the salt, they were utterly disgusting, so if you didn't dump the whole sachet in, you'd just wasted twenty pence. :P

D.F.