Had problems finding this in Spain. Good reminder. I'll see how easy it is to get here.@Marie2020 : this is where the discussion on black ointment begins
https://www.backyardchickens.com/threads/ribhs-dcoopage.1295189/page-1670#post-23455447
Proper name: Ichthyol. It can be used for all sorts of things. Very useful stuff.