Garden Furniture Swing I Have Some Lovely Teak Garden Furniture But It Has Some Black Spots On It, How Do I Clean Them Off?

I have some lovely teak garden furniture but it has some black spots on it, how do I clean them off? - garden furniture swing

I have a beautiful view of garden furniture in teak, that I for many years and I am very happy with it, but this year a few black spots appeared on her what are blackheads, why and how can I clean it? Keep up the furniture as natural as possible.