1892 Gold Dust washing powder
Wikipedia says that the Gold Dust twins didn’t make their first appearance as a soap mascot until 1897, but I found this in a Sept 1892 Ladies’ Home Journal. The timeline looks right if the original Gold Dust twins started their act when William Curry was 8 in 1891. Of course, it’s always possible that they had these two kids as a mascot and then later dubbed them the Gold Dust Twins.
I could be wrong. I mean, here I’ve been paying 12 cents a pound for powdered soap like a crazy woman.