Your starting point from a regulatory perspective has to be a clear understanding on the part of all participants and regulatory stakeholders that the devices in question are no longer medical devices.
If I were you, I'd want the device labeling to state "Training Use Only, Not a Medical Device", as well as your intended "Not for Clinical Use". I'd also verify that this labeling will be applied at a location and via a means that assures that a doctor or other applicable medical personnel could not miss the labeling in the course of normal clinical operations.
If the devices have permanent individual identification, your records should show their removal from medical device status and their transfer to training-tool use.
If the device's packaging context is relevant to the training, the packaging or container used with the training tools should itself be dedicated to that non-medical-device use, and clearly marked to prevent any possible confusion on the part of an insufficiently attentive user.
And, obviously you want to clean and disinfect the devices, and probably 100% inspect them to verify the completeness of the cleaning.
Other than the above, I'm not sure what you have in mind regarding process instructions, PFMECA requirements, etc.