Hi, I am seeing little junk spots on the upper hole area of the bathroom sink. What would be the cause and what would be the best solution ? Any suggestions please.

Upper hole, could you be more specific? Do you mean the over flow? If so spray with tile cleaner with bleach and let it soak for a few minutes before brushing it out.

Yup, bacteria and mold... found in most sink overflow holes! Bleach tile cleaner should definitely do the trick for you as Ballenger pointed out!

Good luck

Mark