Concerning counterfeits, banks & businesses are trained to spot the fakes from the real. If some aren't, they'll get training.
I know, pay for stuff with fake checks, and come up with some fake records so that if the DAESH guys check it, they'll assume it's legit.
Checks can only be used once and it'll take more time to figure out if it's fakey. Once they figure they've been had, the artifacts and gals will be long gone.
Unfortunately this plan can only work for a short while because DAESH will grow wise and avoid checks. However, many women & girls will be freed and antiquities returned.....so it's cool.
Also, send in interlopers who will act as "Harriet Tubman" to the women & girls and STEAL the artifacts from DAESH.
It should be a combo of these methods, constantly rotating in use in order to be more unpredictable to DAESH.