It depends on which type of clearomizer you buy. The Kanger EVOD 2, the Aspire BVC clearomizer can be washed with warm water. Just remove the atomizer head before cleaning the tank. When the clearomizer tank is dry, you can replace the atomizer heads.
We consider our disposable clearomizers a consumable element of our Premier Starter Kit so we don't recommend you try to wash out these tanks. For one thing, they don't come apart (other than the mouthpiece) so cleaning them is not so easy and, more often than not, you might break them in the process. We find most of our customers prefer to simply replace their disposable clearomizers after approximately 2-3 weeks. As a guide, many customers replace their clearomizers with every new bottle of 10mL e-liquid they open - and some less frequently.
If you want to try cleaning your clearomizer, we recommend you use only warm water and no cleaning agents as these will be absorbed by the wick. Remember you'll need to dry your wick before refilling your clearomizer with e-liquid.
You'll notice that inhaling becomes a bit more difficult, and you have to draw deeper. You might also find there is less vapour produced when you exhale.
We do recommend cleaning the base of the disposable clearomizer with a cotton bud tip or dry tissue to remove any e-liquid that might have leaked through from the device if e-liquid has sneaked into the air hole at the centre of the clearomizer tank.
We also suggest you have spare clearomizers on hand.