Well they are harmless and doesn't need any treatment, sometime it will go by itself when you reach 30 yrs.
The first measure to prevent is to prevent excessive dryness,for this you can use mild soap like Dove. And remember single therapy is not so successful in this so combination therapy might be helpful.
You can try moisturizing with vaseline or use of creams with any of the formulation of alpha hydroxy acid lotions,urea, lactic acid lotions, salicylic acid after a bath might helps to soften your skin and remove the dead skin. You can use these 2-3 times daily. If your have severe red rash and inflammation you can use medium potency topical steroid cream like mometasone for a week followed by 2-3% salicylic and 20% urea combination creams.
hydroquinone 4% creams might help fading of the pigmentation. Some research says Photodynamic therapy has been successful but this needs more research for confirmation.
Beside all these medical care, Microdermabrasion has shown some good results to some peoples but research has not still confirmed that it works for all. And yea peoples do try some home exfoliation like taking a hot baths and then rubbing the affected areas with a coarse washcloth or some stiff brush.
There are many therapies like dermabrasion,microdermabrasion,chemical peels,photodynamic therapy,blue light,intense pulsed light therapies. But there is no 100% successful results with all these.