I have brown spots on my face but they are not ...

Well not knowing what techniques you are asking about, I will tell you the solution my grandfather gave me when I had brown spots on my face. He said "Son don't stand so close to the rear of the cow" It was advice that I follow to this day and the brown spots are gone.

Good luck and best wishes. 

Which techniques?

If you are really serious about getting rid of the brown spots, lasers and intense pulsed light devices have been used with great success to remove brown spots. The goal here is for the energy to be selectively absorbed by the pigmented areas, sparing the normal surrounding skin. Topical remedies such as bleaching agents, glycolic acid, and retinoids can be tried but usually these agents are only minimally effective.