Why was the term, "shellbacks" used as an insult toward the turtles?

[gobo]

Originally Posted by CyberCubed

"ol' metal mouth"

When? Out of those nicknames for Shredder in Turtles Forever, I couldn't remember ANY of them being used in the show. But, that one, I vaguely recall Michelangelo saying before.

Originally Posted by CyberCubed

I admit that "tin grin" always brought a smile to my face.

And, a make-believe "grin" to Shredder's...