Hi Srinivas,
All black spots on the face are not moles. It could be freckles,Lentigens, melasma or post inflammatory hyper pigmentation (caused by primary problems like acne, rash, scratch mark or an injury to the skin).
The treatment and results in all the different types vary. Hence it is first important to diagnose the cause and then treat it accordingly.
I would suggest a visit to a dermatologist for getting the skin lesions diagnosed first.

1)Use a sunscreen whenever you step out of the house/office
2) Was your face with soap and water atleast 2 times/day
3) Avoid vigorous rubbing and wiping your face.
4) Drink plenty of water and have a nutritious diet including vegetables and fruits.

Once we know what you actually have, treating it gets easier and effective !!!!

Dietary Treatments for Moles
Potassium is very beneficial to people who wish to get rid of their moles.Apples contain a high proportion of potassium,especially in the form of apple cider vinegar.Other fruits that contain potassium are avocado,bananas and grapefruit.Potatoes,mushrooms,tomatoes and spinach are also good sources of potassium.
..Cut a pineapple and apply its fresh juice on the moles.Repeat this several times in a day.This is a quick method to get rid of the moles.Within just a couple of days,the moles will diminish and fade out.
.Honey by itself has curative properties to remove moles.Apply some honey onto the moles each morning.
.Prepare a mixture of finely ground flaxseed in flaxseed oil.Add a dash of raw honey to the mixture.Apply this on the moles everyday. Within a couple of weeks,the moles fade and disappear.