Yes, they were paying money for the return of leftover bits from disposable weapons.A request for your own benefit!
If possible, make sure spent tubes are returned. The home front needs them to send you a new Panzerfaust. Additionally, bounties are paid for their return.
In that case, another fun bit of trivia concerning reuse late in that war: German soldiers apparently developed a habit of chopping the heels off their boots, then requesting replacements (not sure if that would be whole boots or just the heels). You’re probably wondering why on earth they would do this … Well, because of wartime scarcity, new heels were severely rationed for civilians. Soldiers, on the other hand, were not rationed … so if dad back home in Saxony or Westphalia had worn out his shoes’ heels, son in the trenches would chop off his and mail them homeI knew that in WW1 they brought shell casing back for reuse