What does this mean? "Those things don’t work worth a damn."
I read about this interesting article and it was about a trip to Italy. Somewhere in it the writer said that she was puzzled by some Italian-styled pieces of equipment. At first there was this backless toilet without a flusher but with two flush buttons on the wall, and then there was this hairdryer on the wall with a vacuum cleaner hose. After that she said, "Again, my utter immaturity could not be held back as I laughed myself silly as I dried my hair with the vacuum nozzle. Those things don’t work worth a damn, by the way."
I know what "not worth a damn" mean but I don't understand "not work worth a damn", because as far as I know, the word worth is normally preceded by a verb to be.
So what does "Those things don’t work worth a damn" mean or can you paraphrase it for me? Many thanks to you in advance.