Arturo I used MANY a shell for frag bases when my mother lived near the beach. She collected shells every couple of days and once a month or so I'd get a box in the mail packed up. I probably still have 1,234,567,876 shell saved for future supplies LOL!
Congrats on the new FRAG endeavor. Just realize it's addictive! Once you go FRAG you never go back LOL!