Be Good.
"Ayb a flig vat arein in dyn room vot er not gehat avu zich avec stu shtellen."
From Yiddish to English this roughly translates to:
"If a fly came into your room he would have no place to land." Meaning, clean up.
My great grandmother used to say this to my grandmother. My grandmother used to say this to my mother. My mother used to say it to me.