Tooth powder (late 1960s/early 1970s)

When I was little, my dad used to use tooth powder. (Who knows, maybe he continued until the day he died, but I only remember it when I was little and living in the Bay Area.) One fine evening, a curious little girl decided to see what would happen if she stuck her finger in the tin. Answer: it'll get stuck and you'll have to call for help + a very sore finger.