My Mom used to do the "penny for a knife" thing; for some reason I always thought it was a holdover custom so one wouldn't use a weapon against a supplier, though that looks sort of stupid when I write it down like that. Also, if a drinking glass broke in her hands while she was washing it (and didn't cut her), she'd break a match and put it into the bottom before throwing the glass away. I have NO idea what that was all about.