I have come across this type of stain a few times now with varying success, the last time i emailed Paul Pearce who pretty much agreed with the advice i got on here, rinsing with f and f rinse ending up using Prochem coffee stain remover, it got most of it out but i was not exactly grinning from ear to ear at the results

Anyway i have searched the forums for more ideas and i keep seeing sodium met and Hydrogen peroxide as alternatives, now did i miss this on the two spot and stain courses i went on as i do not remember it being mentioned, its definatley a possibilty but its as though this is some well guarded secret on the forums its offered as a method that works but thats all you get no practical idea of the procedure.
As i have another wool berber with a week old coffee stain on it i thought i would see what other alternatives are availlable, i do have my microsplitter spotter from solutions, and my specialist stain remover from Alltec the mild bleaching one of last resort

thought i would try rinsing with just cold water first then go from there.