Regret to inform you that it's unlikely you'll get it out, as there are two dyes in Irn Bru .....sunset yellow and a red, forget the name.
Ive had success with Argosheen, in the past, but I bought it from the USA and unfortunately don't have any.
There is an old c/c trick which involves ' high heat ' usually delivered with a domestic iron, through a clean white towel ........the only danger, is, you might suffer colour loss.
In most cases we suggest they check their insurance policy........
r m