Big fat Cornish pasties were the perfect lunch for men working in the Cornish tin mines. The thick pastry kept the contents of the pasty secure and warm. Housewives would make one for each member of the family - often stuffed with meat and veg at one end and jam at the other - and mark initials on the pastry to avoid fist fights.
There was a belief among miners that it was unlucky to eat the thick crimped crust and it should be thrown to the ‘knockers’ (the spirits of the tin mines). There was also a practical benefit.
Miners used the crust as a handle to hold the pasty while they ate, so avoiding transferring arsenic, a deadly poison present in the mines, on to their food.