This extraction is quite a hard nut to crack and needs trying, but it's practically free, and yields nitrates! For anyone that can't buy them in store (anymore) it's a great option and a skill to learn.

I hope you like the video! Have a nice one.

Link to the full resolution conceptual map: https://photos.app.goo.gl/eb9CoE1sBjT...

Read more on the theme of historical saltpeter extraction here:
http://firearmshistory.blogspot.com/2...
http://salt.org.il/frame_saltpet.html