They’re melted down and the result is pure untraceable metal. Rhodium vendors can’t be common though. What’s the story the fences give? “This is all from my small-scale family rhodium mine”?
I suspect with Catalytic Converter thefts, the CATs are small enough and light enough to be shipped abroad
They were eventually caught with container loads of cat's on their way to Europe.
And then you sell it to an actual rhodium mine who just so happens to be particularly productive that month.
Surely its easier to keep an eye on all rhodium mines, rather than trying to keep an eye on all scrap metal yards.
There must be limited facilities with the ability to extract and purify the rhodium content.