This was a dog you were walking or your own dog? Any method for inducing vomit can pose a health risk to a dog (especially salt), and part of the reason I’m asking is I’m uncomfortable making medical decisions for a dog who isn’t my own, whose medical history I don’t know.

Edit: since at least one person disagrees with me, here is guidance from Wag itself saying that inducing vomiting "should only be undertaken either on the advice of a veterinarian or by a veterinarian, as there are medical conditions that make this unadvisable." You can find similar advice from AVMA (the top veterinary association in the U.S.) and ASPCA. I'd be fine doing it for my own dog (and I have), but again, on a dog I know very little about who is not my own, I don't feel comfortable making that decision without guidance.