The Ecca shales contain some of the best coals of South Africa, but the seams contain much unmarketable coal.
If these celebrities are participating in this show in order to boost their careers, they may be in for an unwelcome surprise when it does just the opposite and makes them "unmarketable."
For example, the company's books tell you whether the company is insolvent, but they do not tell you whether its product or service is unmarketable or no longer in demand.
It wasn't until 1982 that the defiantly unmarketable band made the UK Top Ten chart with Pornography.