Purification of Amana Funds

I was reading one of the previous posts regarding purification and @Mufti_Faraz_Adam mentioned that some are purified at fund level and some need to be done by investors. I got in contact with Amana to find out more and this was the response.
Hopefully this is beneficial for others.

Assalaamu alaykum,

Jazakallah khayran for finding this out.