Revoking rank, it is acknowleged. does not mean revoking skills. Once learned, martial arts skills can not be taken away.
However, revoking rank or cutting someone from an organization means they no longer have the authorization to teach from an accredited Instructor or Organization. You can physically teach, but you cannot use my name, I will not recommend you to test again, and I will not judge for you. You are basically on your own.
Unless you acquire students who only care about physical technique, you really lose any semblance of legitimacy because you cannot use your Instructor as a reference and you cannot claim organization credentials.
If you want to teach, students will invariably ask who your Instructor is, because no school exists in a vacuum. Every Instructor is in some way linked to other schools, whether by mutual Association, Instructors, or whatever. It is what helps schools to succeed. By revoking someone's rank, even if you cannot revoke ability, you cut off this synergistic process. Physically you can still teach, but you have no support system.
And no legitimate Instructor would support a black belt who has been cut or had their rank revoked, although many low class ones would accept any students who wanted to join them. A high class Instructor would tell such a black belt "You must work this out with your Instructor. I will not accept you just because your Instructor cut you or revoked your rank."
An internet search will turn up MANY Instructors who will accept any students regardless of rank, style, or circumstances.