Green’s Dictionary of Slang

soap-locked adj.

[soap lock n.]

wearing soap lock n.

[US]W.T. Thompson Major Jones’s Courtship (1872) 140: Do you think [...] he could recognize his countrymen in the starched up, soap-locked, high-heeled, sickly-looking dandys of the present day?
[US](con. 1840s) in A.F. Harlow Old Bowery Days 193: The hair which is smoothed with soap in puffs below the ears, and in large ringlets around them, [...] has given birth, we presume to the word ‘soaplock’.