without intelligent pruning

Few eyebrows are perfect without intelligent pruning.

Larison, Ruth. 1942. Those Enduring Young Charms. Harper and Brothers. p. 155

units of charm

If it were possible to put a voltameter on the world’s superwomen, the electromagnetism would be expressed in units of charm, style, personality, poise, beauty, attractiveness, good manners, knowledge of men, conversation, smartness. These are the alternating currents which determine the degree of a woman’s voltaic power.
Archer, Alma. 1941 How to be Smart and Charming. New York. New York Personal Improvement Guild. Book One p. 24

they must be the allies

Always remember…the face of a clown is grotesque because it is meant to be. If cosmetics are to add to beauty they must be the allies, not the enemies, of nature. 

Post, Elizabeth. Emily Post's Etiquette. New York. Funk and Wagnall's, p.582

loveliness can be learned

Loveliness can be learned in the same way you learn to play the piano or make a cake. 
Larison, Ruth. 1942. Those Enduring Young Charms. Harper and Brothers, p. 230

as mysterious as a glass of water

Mystery adds charm. Some women are about as mysterious as a glass of water.  
Alma, Archer. 1939. How to be Smart and Charming. New York. Personal Improvement Guild. book one p. 20

spotlessly clean to the end

Marie Antoinette, with only the crudest conveniences, kept herself spotlessly clean to the end. And when they called to take her to the guillotine, she asked only for the time to put on a clean shift. 

Wilson, Marjery. The Woman You Want to Be. 1942. Philadelphia. J.B. Lippincott Co. p.68