I could brain him with his lady's fan (1 Henry IV., ii. 3)—i.e. knock his brains out with a fan handle. The ancient fans had long handles, so that ladies used their fans for walking-sticks, and it was by no means unusual for very testy dames to chastise unruly children by beating them with their fan-sticks.
Wer't not better Your head were brokeu with the handle of a fan?
Beaumont and Fletcher: Wit at Several Weapons, v.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894