The answer is it depends. Traditionally (as in normally) the CE4 is a completely disposable clearomizer with no parts that unscrew (except the drip tip to fill it) and the CE5 has a base that will unscrew from the clearomizer so you can clean it and replace the coil head.
Now some companies sell CE4s that can be dis-assembled and some sell CE5s that are disposable.
So that's as clear as mud then...
