I had a milk bleb (clogged nipple pore) that started to cause a clogged duct and I used the haakaa silicone pump with epsom salt and baking soda and very warm water to draw crap out. I also did massage after hot showers and warm compress.

I second sunflower lecithin - specifically for prevention too.

When you breast feed, position your baby so her chin is toward the clogged duct. This works for me every time! It helps direct the suction toward the duct. (And massage the area during feeding.)

I have also had good luck with the LaVie lactation massager.

Sunflower lecithin pills help me a lot. I take one daily while nursing and if I am fighting a clogged duct, I take up to 4 pills. I also do pretty aggressive/hard compression towards the nipple while the baby is feeding (or pumping). Manual massage/pushing while in the hot shower can help too. I also try to use a manual pump often. Good luck!