What is the best way to clean a conch shell?

Aloha all!
I found a great conch shell while snorkeling in Cozumel last summer and I followed the suggested directions on the internet. After I soaked in diluted bleachwater to kill off the growth..it's bright white! I have sanded off alot of the calcium to show streaks of pink shell and wonder if there is a better way. Any suggestions?
Thanks