OK, so my grandad (UK) worked in an ordinance factory in Ireland during WW2. He died in 1989 and when we cleared his office desk, we found an envelope with 2 postcards of Hitler and an unworn swastika arm band. No one is sure wtf it's all about. The logical answer is that he worked for a number of German electronics firms before and after WW2 and the postcards and arm band were no different in 1937 to a MAGA hat and postcard of Trump is today... But a part of me says there's more to the story but I have no living relatives who can shed any further light on it. And there's nothing about him online as far as I can find. My other grandad was a major in the army and a POW in Burma, we found loads about him online and my dad learnt loads from him before died.
TLDR found a 1937 Swastika armband in my British grandads drawer when he died, no idea why he had it.