There is, in fact, a sort of truth in what was said. Throughout the war people were encouraged to "contribute" to the war effort by donating their aluminium pots and pans "to make Spitfires" and their iron railings, ornate gates and garden seats to make "guns and tanks to fight Hitler". The objects collected - in thousands - were obviously not much use for their advertised purpose but part of the idea was make people feel they were making a sacrifice and were therefore more involved in the "home-front" war effort.
Much of this metalwork - particularly the cast iron - was used to make bomb casings and the aluminium to make incendiary cases.
So, indirectly, railings, garden seats and saucepans were dropped by the RAF on Germany !