Should I do warm or cold compress when I have a blocked duct?

My masseur who did my post natal also recommended me to use a warm towel, best if I can put a warm towel on my boobs every 2-3 hours. However, prevention is better than cure so be sure to breastfeed often and to empty out your boobs via pumping to prevent it from occuring again! http://www.drugs.com/cg/breastfeeding-and-plugged-ducts.html