You would want to utilize the new ->
https://docs.arnoldrenderer.com/display/A5ARP/Nested+Dielectrics
Initiative.
You give your elements a value in the hirachy, study the article to learn how to approach the layering, so you get a realistic render going.
As I see it, you need 4 elements.
- The plastic bottle
- The gold fragments
- A lot of deformed micro air boubles
- The gooy liquid ( not water )
I can see you already run out of transmission depth, because you have black spots.
Now I can also see you attempted to raise the transmission ray depth, but that is only half the equation, you need to raise the max 10 in the section beneath, when you up that number, you allow for more ray bounces and the black will go away.
So I would focus on making all the micro airboubles, and your gold pieces looks alright by first glance, and play with the roughness of the liquid, it is not crystal clear, but the more boubles the less fake manipulations needed, you could seed 10 million boubles, but you need to clump them and only make 0.1% large, meaning somewhat visible, the rest has to be microscopic and just form a mass of unclear soapy stuff.
After this, you can start to play with the Nested Dielectrics sequence so your elements are rendered realistically, based on the article I linked to in the start.
