Ichthammol is impossible to remove from anything, IME. Anything I'm going to use with it is considered disposable as it is easier to trash than try to get the stuff off. Had to use ichthammol on a jaw abscess one time and it was everywhere...halter, fly mask, stall, me....hate that stuff, but it does work. Afterwards, I did try washing halter and mask, but ended up tossing them, and scraped what I could off the stall. Think I threw away a jacket that got icht'd too!
First phase, soak & hand scrub-brush the spots with Dawn, slightly dampened. Took out 80% of the stain. May Dawn again after dry, am thinking of trying Resolve or Oxyclean? Never had much luck on greasy stains with Oxyclean.
Anybody ever use their husband's Goo Gone, orwhatevs, mechanic's hand cleaner?