How do you clean your PVC plumbing?

[jgln]

I was concidering using all PVC from my main tank to sump and back, previously used a combination of soft tubing and PVC. My problem was sponges growing in the tubing and it needed to be cleaned out from time to time. Now I know with all PVC there would be no light, but does anyone have a need to clean their PVC plumbing and if so how? There are a lot of elbows I see in most systems and once connected would be difficult to clean.

Thanks! (I did check the search but nothing)