Baking soda and marble

BobVila’s article, How to: Clean Marble resulted in disaster. Stains deepened after applying baking soda, water and covering with plastic for 24 hours! Disaster! $900 Table top ruined. Many articles about baking soda and cleaning stains on marble, except one that warned against I s use. But there was Bob’s article among the ‘how tos’, so I trusted it to go forward. Sick to my stomach.
Brenda