Blocked tear duct in pet dog

Just thought I should pass on some good news. Our vet is very knowledgeable in alternative health solutions for our dogs.
Recently our labradoodle had a blocked tear duct following an infection. His advice was to place a drop of black slightly salted tea in the corner of her eye twice a day for a couple of days. It has worked liked a charm. Just ordinary fairly strong black tea with a pinch of salt to about half a cup. Apparently it is very astringent.