The People's Operator has a US based customer service team. They are positioned as a carrier who is socially conscious and they will donate 10% of your monthly bill to a charity of your choice. You don't need to do anything, TPO will take care of it all for you.
Seashells contain calcium carbonate. The calcium carbonate reacts with the acid in the vinegar and causes carbon dioxide bubbles to form. Even though the acid in vinegar is weak it can, over a period of time, dissolve shells.
The calcium carbonate content of limestone gives it a property that is often used in rock identification - it effervesces in contact with a cold solution of 5% hydrochloric acid. Chalk: A fine-grained, light-colored limestone formed from the calcium carbonate skeletal remains of tiny marine organisms.