Surface rust inside fuel tank

Hi every body,
Just before the website crash - I was about to start cleaning inside my 1966 125 Special fuel tank using Phosphoric acid as describe in the 'forum' - then the crash came & I hadn't noted the dilutions like a twit! Can my fellow lammy owners come to the rescue again please?
Thanks
Sherpadean
Just before the website crash - I was about to start cleaning inside my 1966 125 Special fuel tank using Phosphoric acid as describe in the 'forum' - then the crash came & I hadn't noted the dilutions like a twit! Can my fellow lammy owners come to the rescue again please?

Thanks
Sherpadean