I have a section on Cornish superstitions, but I thought this material on Cornish supperstitions of the fairy should be in an article here, under Cornish Fairy folklore.

It was once a common custom in East Cornwall, when houses were built, to leave holes in the walls by which these little beings could enter; to stop them up would drive away good luck.

In West Cornwall knobs of lead, known as pisky's paws or pisky feet, were placed at intervals on the roofs of farm–houses to prevent the piskies from dancing on them and turning milk sour.

Country people in East Cornwall sometimes put a prayer book under a child's pillow as a charm to keep away piskies. I am told that a poor woman, near Launceton, was fully persuaded that one of her children was taken away and a pisky substituted, the disaster being caused by the absence of a prayer book on one particular night.