@Fire Fist:
How about an island of crap? The whole island is crap, the main bad guy ate the Kuso kuso no Mi, and the buildings and food is dung.
I can picture Sanji there:
"I've had it with this shitty shit on this shitty shit island!"
It would be easier if it was the waste produce of the island fish like that one seen at the end of Little Garden. Where an entire town has grown up on a pile of crap, hey they would at least be able to grow lots of food there seeing as the soil is well fertilized!