Goldpick
Chris Johnson
Only just noticed this this article, quite interesting read to see results from using different mediums, and what they recommended in the end to use as the safest and most thorough methods. Please note that this is a direct link to the PDF.
https://www.google.com/url?sa=t&sou...WMAF6BAgIEAE&usg=AOvVaw2kH41ZPcGFkC0v_7suorkH
https://www.google.com/url?sa=t&sou...WMAF6BAgIEAE&usg=AOvVaw2kH41ZPcGFkC0v_7suorkH