When my mother passed she left some pearls to my wife. We actually forgot about them until yesterday when we purchased another strand and found these when she went to put the new ones away. These strands had not seen daylight in probably 15+ years and I thought it prudent to "gently" clean them in a dilute solution of dish soap and spring water with a spring water rinse using microfiber cloths. I photographed the strands prior to cleaning but didn't think to zoom in close. After the cleaning I noticed on what I believe was here oldest an favorite necklace (center) substantial damage to the outermost Nacre. My question is if I didn't notice this level of finish erosion prior to the cleaning is it likely I did something wrong? I ask because I had planned to clean other small strands my wife has accumulated over the years and don't want similar results. Thank you for any advice!!