I like ur idea with capacitors but abour new ways to use rubber and resin
Resin often used for solder or for phenolic board as insulating material

Rubber gaskets to prevent leaks in pipes
Flexible rubber hoses in pumps
Rubber drive belt for motors
May be some as insulating material for capacitors

Hello !
In the game I use (Bob + Angel + Kao extended) :
Resin used in solder and my mod use lot of solders :)
Rubber is used in insolated cable who is used in I/O interfaces. (the biggest I/O interface use more than 60 rubber in the recipe)