Cleaning Breast Pumps

You cannot really clean the pump - there is no reason to clean it unless you've spilled something in it, and even then, you'd have to take the pump apart and put it back together correctly and in its case. It is electrical, and you cannot use any sort of liquid on it - contact the manufacturer, or risk destroying it if you try to clean it yourself.
No fluids ever enter the pump itself, though there usually isn't any reason to clean it ever. Why are you needing to clean it?

Call the manufacturer. I have a Medela and it was 5 years old when I had my son, so it was a little sluggish. I called and they helped me clean it and it worked fine. Doing it yourself might hinder the warranty. I would call them before you do anything on your own.
Good luck

If it is an electric pump, contact the manufacturer, or look on their website. You don't want to even open it up yourself without expert guidance. If it is a manual pump, again call the manufacturer, but you should be able to do this yourself.
Did you get breastmilk backflow up the tubes into the pump mechanism? Don't worry, that happens! Just give them a call and they'll set you straight.

depends on the brand and type of pump. you may want to contact the manufacturer.