I re-read “The Secret Life of Walter Mitty” recently. At one point, he tried to remember what his nagging wife wanted him to buy at the store; one of the possible items was “Squibb’s.” Was that a brand name, or a misspelling of “squib,” or what?
Hmmmn. I was certain that my answer of “A non-magical person born to magical parents” was going to be imminently useful here; but I see not.
Probably a product of Bristol-Myers Squibb.
I’m going to guess that it was a sort of toothpaste at the time. Cite
I immediately thought of squib - Wiktionary, the free dictionary , but somehow I wouldn’t picture Mitty’s wife as a fireworks fan. 
Having grown up near a Squibb plant, my immediate thought was runner pat’s . The firm was run by the family for four generations, and I think it merged with Bristol Meyers after Thurber wrote his story. They made lots of pharmaceuticals, so I have no idea what Mitty’s wife wanted, but it was undoubtedly some health or beauty aid.
My folks used to buy their Mineral Oil. I think my Mom used it for makeup removal.
I thought it was cough drops.
It’s definitely a product of Bristol-Myers Squibb, but the problem with the toothpaste theory is that toothpaste is listed separately in the story. My guess, given the items mentioned alongside it, is shaving cream.
I have a huge, ancient bottle of Squibb’s Mineral Oil in the bathroom downstairs. I don’t recall anyone in the family actually using any of it for the last 50 years,but there it sits.
Hmm… I looked, but unfortunately I threw out my old English 101 notebook…
*Thread followed, nonetheless!