My friend also suggested massaging. Massage from the clogged area towards the mipple.
She referred to this article for some tips on treating plugged duct:
http://www.homeremediesweb.com/blocked-milk-duct-home-remedy.php
According to the article, it is suggested that after massaging the breast with the lump, use the thumb and index finger to try to squeeze out the blockage. Start by placing the fingers at the outer edges of the areola, and then press down and squeeze the fingers inward toward the nipple. Be sure to have a towel or cup close by in case milk begins to flow or spray out.
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