Clear cached PuTTY's SSH keys

For all those of you who have been trying to clear Putty’s cache of host fingerprints (Windows) for development or testing, here is the answer:

1. Open the registry (regedit)
2. Go to HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\SshHostKeys
3. Delete the rows that you need and presto!

Nice, TIL.