Dead sand dollars for Frags?

[sum1famous]

just wanted to find out if anyone has used dead sand dollars for frags. if so do i need to cure, boil or do any thing to sanitize them? thanks in advance.
these were collected by my kids at beach.

 

[30-xtra high]

never used them before... they'd most likely work, but you need to boil them. when they wash up on the beach, lol, they pee all over themselves, don't know why?, but they do. so if you just toss them in, you'll have an amonia spike, just boil them and they'll be fine.