The wadding inside the carto will still have some liquid in there,
but it would be anybodys guess how many draws you could get
out of it, it depends on how thick the liquid is, exactly how much
is left in there, And the length of each draw that you take.
So yes you can do it, but its just knowing when to stop, and if you
don't stop in time, then you will end up burning the wadding as it
Depending on your previous flavour the new flavour will come through
after a while, unless it was a very strong first flavour which can linger
for absolutely ages.
Hope this helps a little