There are few things that can be done and these spots can be caused by sun exposure and as part of the aging process. There are some lasers that will lighten the spots.
Lemon juice is an important agent in reducing brown spots. Can use aloe vera gel,red onion, sour milk as these have the tendency to bleach. Can also use fruit/vegetable masks
For brown sots on the skin,use some lemon or turmeric mixed creams,soaps. They have the tendency to remove any spots in the skin. For better results, use them frequently. It also kills germs.
Remedies to remove brown spots vary. There are many over the counter ointments or creams that can be used along with some prescription medicines that can be used.