Ah, thank you, now I understand it. One of the rare occasions I couldn't translate it myself, Google didn't help either :)))
There is a similar Bulgarian phrase "кирливи ризи", similar to the English "dirty laundry", but I don't we have a proverb, or at least I can't recall one from the top of my head :)))

This phrase "вадя кирливи ризи" is particularly popular in the modern political life here, when opponents start digging and throwing dirt at each other so they win more votes.