Remember that many keys from the British Railway Network, including the very old ones, are Master Keys and still in use today, and as such will give people access to areas which may be restricted and a danger to life. These keys in the wrong hands can KILL.

Such keys are, 222, 221, BR1B and Loco/Locomotive keys.

My advice is eather destroy them, donate them to a Preservation Railway or hand them to a Railway Company Employee.