Concept

The concept is to immerse components in a liquid and seal it. The liquid for starters should be non conducting (electric), good conductor of heat, immiscible with water, should not degrade, hazard free and readily available. 

After some research I concluded some sort of oil should be used. Common cooking oils were out of the question because it would decompose on heating and would go rancid with time leaving gooey unwanted stuff growing and leaving residue. Synthetic or mineral oils would start degrading at a higher temperature but then most of them are corrosive or flammable and fume.

Liquid Paraffin also known as mineral oil is a suitable immersion medium. It is odorless colorless, bad conductor of electricity, good conductor of heat, has a very high flash point, not reactive and immiscible with water. It has lots of applications including medical hence it is readily available. It does not turn rancid either.