When you're at work, the best part about washing your pump is that you don't have to!  Breastmilk has wonderful antibacterial properties, and shows no significant bacterial growth after almost a full day at room temperature.  I'm not saying to just leave your pump parts sitting out, but you'll be fine if you just wipe the drops of milk off with a paper towel or tissue, then stick the horns, bottles and tubing in a bag in the fridge, or place the whole works in a cooler pack.  This is just about the biggest time saver for a W&P mom.

 

At night, you should wash the flanges, valves and collection bottles thoroughly each night.  Again, because of breastmilk's antibacterial properties, sterilization is not necessary.  If your water temperature is at least 140 F, you can wash the parts in the dishwasher (or if your dishwasher has a heated cycle, just use that).  In fact, many moms run the dishwasher every night, even if all it has in it is pump parts, just to save time.

If you're not washing them in the dishwasher, hot soapy water does the trick.  I used to sterilize the whole kit in boiling water once a week on the weekend, just to make sure it was totally clean.

 

If you have milk back up into the tubing and need to wash the tubes, wash them in hot soapy water, rinse well, then boil to sterilize (since you wash them so rarely, they should be sterilized).  To get rid of condensation in the tubes or to dry after washing them, drip some rubbing alcohol in one end, then go outside and whirl the tubes around over your head until the alcohol comes out the other end.  Once the alcohol evaporates, the tubes will stay dry inside.