I assume you are talking about eGo-C and eGo-T tanks (there are also eGo cartos/cartomizers, they have filler in them).
Tanks can not be taken apart, but they can be rinsed out with plain water. I never noticed any liquid stuck at the top; the only liquid I do notice is a little condensation on the outside of the tank and it's normal. Just wipe it off with a tissue.
eGo-T and eGo-C atomizers can and should be cleaned just like Lydia described above.
If you're asking about eGo cartomizers, please start another thread and describe where exactly the liquid gets stuck...
This is an eGo cartomizer:
https://www.cignot.com/product_p/ego-cto-alb.htm