To tell Nami and the others apart after their souls were swapped, Usopp made paper face portraits of them and stuck them onto their respective foreheads.
Franky (Nami): "Until we can switch back, this is the only way. And Sanji, you just peeked at my body again—that'll cost you 200,000 Berries. From now on, too, every single time you dare look, I'm charging 200,000!"
Nami (Sanji): "So expensive! Xiaohu, can you spot me some cash?"
Chapter 95