This test is also called as "smell test".
Hot temperature (when smoke starts to come out) enhances smell of plastic. In other colors pine smell is strong enough to overcome plastic smell, but in such light clear amber testing temperature is very important. So do not burn it - touch with hot metal and smell it right away.
In one of the videos in Youtube I saw woman saying that amber is a bit gummy, my face expression was like that: o.O ... because copal might be gummy due to young age (1-5 million years old) and process of polymerization did not went so far in it like in natural Baltic amber (age 40-60 million years old).
Copal can go through most of the tests which amber goes through, but usually it is in more gummy state than amber is and has more sweet smell that amber does. Amber's hardness is similar to nail hardness, so it is quite hard and not gummy for sure.
If you see air bubbles in stones, you know that it is glass fake. This does not work on Baltic amber. Some amber pieces do have air bubbles and from those bubbles scientists got information about what atmosphere was on earth 40-60 million years ago. So if you see bubbles in Baltic amber, it does not mean, that amber is fake.
What is amber and Baltic amber?
How Baltic amber can be used for healing and what is amber acid?
What is amber for? (some information)
About ambers of the world and copal
Who am I? (about me)
How to choose Baltic amber teething necklace?
P.S. I am sorry for mistakes - English is not my native language.