Clearly Lois hides diamonds in her coal-scuttle; let's face it, she's just the type, and what's more, she probably has more diamonds than she knows what to do with from the days she was dating Superman.
Yes, that would make a great story: what did Lois do with all the treasures she received from Superman? My favourite gift, never delivered, was the perfect pearl necklace Superman was making to give to Lois in the event of his death (he also worked on a sports car for Jimmy).
Whenver he had a day off, Superman would scour the ocean for perfect pearls, slowly accumulating them over years.