This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
To avoid losing a fancy hairpin, bend one leg of the pin as shown in the illustration. The hair caught in the notch formed by the bend will prevent the pin from dropping out. - Contributed by W. C. Loy, Rochester, Ind.
Ill: The Bend in the Pin will Hold in the Hair and Prevent the Loss of the Pin
A metal surface polished with oil will keep clean longer than when polished dry.