I'm specifically referring to the "beak," or spike, of it being embedded in the planking of an enemy vessel. Once storming and capturing a vessel, could it then be removed from the captured vessel and used again in the same battle? How easy was it to remove?
You will not find definitive answers as we have very limited sources. You seem already familiar with the device's use though which helps. If I can speculate I would say that the Corvus could certainly be used more than once because otherwise you would have been stuck to another ship, thus terribly exposing the user to subsequent ramming.
It seems likely that the boarding ramp and hook could be removed from the enemy vessel without too much hassle. Remember that these devices could be taken down and removed from ships so there was surely a way to remove a ramp that could not be dislodged. If the Romans found that this happened often enough then I'm sure they found some sort of solution such as spare parts. I would think that the boarding hook however could be pried out from the enemy deck and simply needed to be cleared of debris to be used again.