I have seen packages that say natural... for both jute and sisal... that I would NOT use with my FIDs..
I get really strange looks... cause I sniff them before buying...

.. several times I have passed on purchasing ... because the rope/jute smelled of petroleum products....
The product itself maybe natural ...

.. but the machines and process that make it sometimes use the petroleum oil... that would make the produce not bird safe....
So now I am a rope sniffer ... to add to my other strange habits...