How to distinguish sofa sponge is rubber sponge or recycled sponge?

How to distinguish sofa sponge is rubber sponge or recycled sponge?

Recycled cotton is easy to recognize! It is made up of small pieces of broken sponges! Such cotton is not durable! It will be deformed after a period of time! I won’t meet where I sit down! There are also many kinds of rubber wool! It mainly depends on how it foams! The denser the sponge, the better!