Loads of the iron railings went (no iron bombers though!) and lorry loads of aluminium pans etc. were collected. Although some of the material was used for the War effort, I think the major aspect of this campaign was to raise morale, and give ordinary folk a feeling of participation. A lot of the scrap lay in piles until years after 1945.
The salvage of milk bottle tops was a late 50s and early 60s idea, but here the material was reused and was a way of engaging children in charitable efforts.