I sell U in Hong Kong and exchange it for Hong Kong dollars, buy gold with Hong Kong dollars, and then sell it directly in Shenzhen or Guangzhou. In this way, I can make a profit from the price difference of gold. The procedures are completely compliant, and I can even issue invoices and sell the invoices to logistics companies to make another profit. To be honest, the control of the mainland is like a mere formality to me. I can't say that it is for me, but it is full of loopholes...