For what it's worth, cupric chloride is/was used as an etchant and hydrochloric acid is used to refresh the solution. There's a bit more to it. A good friend of mine prefers this process for his hobby level work.
If you surf enough you'll find MSDS sheets. A note of caution - the MSDS sheets may not contain enough information to protect you from the hazards that could result from your process. Even simple cleaners used in the home, that are safe on their own, can be hazardous if mixed.
My recommendation would be to follow a process and purchase the materials, solutions, etc from a supplier - that includes instructions on the safe handling, the process, etc.