тут игра слов
Rubbish - здесь означает "плохая" (шутка)
а игра состоит в аналогии - Rubbish - dustman - помойки

"My Old Man's a Dustman" - название песни. См. ссылку

Lonnie Donegan – My Old Man's A Dustman Lyrics
Now here's a little story
To tell it is a must
About an unknown hero
That moves away your dust
Some people make a fortune
Others earn a mint
But my old man ‘e don't earn much
In fact he's flippin' skint

Oh, my old man's a dustman
He wears a dustman's hat
He wears gorblimey trousers
And he lives in a council flat
He looks a proper narner
In his great big hob nailed boots
He's got such a job to pull 'em up
That he calls them daisy roots

Some folk give tips at Christmas
And some of them forget
And when he picks their bins up
He spills some on the steps
Now one old man got nasty
And to the council wrote
Next time my old man went 'round there
He punched him up the throat

Oh, my old man's a dustman
He wears a dustman's hat
He wears gorblimey trousers
And he lives in a council flat

Мне кажется, тут надо отойти от дословного перевода. Приведенный привет - как вариант. Нужно подобрать пару, которая тесно ассоциируется между собой (как "дворник - мусор"). В моем примере "мусор" - в смысле "ерунда, нечто незначительное".