They collect latex from the rubber tree by tapping it and let it drip into a bucket and wait till it stops. It is then processed and various chemicals added, predominately sulphur to allow it to be...
You can use either term. 'Burned' and 'burnt' are variations on the same word, just like 'learned' and 'learnt'. So you could say, 'The car smelled of burned rubber', or 'The car smelled of burnt...
by collecting its sap. you kind of make a hole or slice... a small one, something like that then put a tube on it then a pail whih collect the falling sap...