I cannot imagine that they would employ civilians to go and collect up scrap in the Front Lines, or No Mans Land and maybe, not even behind the lines, so I'd have thought that any military equipment would have to be collected by Soldiers.

Any waste 'back at barracks', or 'stations at home' could be easily handled by civilians without putting them at risk.

The historical pictures show that the rifle salvage seem to have been organised by the military.
The third picture is embarkation, leaving the rifles (presumambly) for incoming troops


WW1 Battlefield pick-ups




WW2 Battlefield pick-ups





WW2 Handing over rifles prior to embarkation