Fairy Soap
N.K. Fairbank Co. was founded in 1875 and produced Fairy Soap. The ad that presumably ran in the 1940s shows a little white girl asking a Black child why her mother won’t wash her with Fairy Soap, insinuating she is Black from dirt.*
*Fairy Soap was originally created by N.K. Fairbank, before Procter & Gamble buys it.
Source "Atlanta Black Star".