Technically, since there is no mechanism in the Constitution for the removal of an amendment, which has been passed by Congress, and signed by the President and on which the ratifiaction process has begun, IF the Amendment does not contain a time limit for ratification.

SO this Amendment and its associated Amending process is still active and could become an Amendment to our Constitution (even today) IF it were to recieve the necessary number of endorsement from the required number of states.

If it were to become an Amendment, then there could be a process begun to remove it, like the prohibition Amendment. But as it is, for now, it is technically still active "On The Books" waiting for the necessary number of state to ratify it.