  We demonstrate that the X-ray iron line fitting technique can be leveraged as
a powerful probe of the cosmic censorship conjecture. We do this by extending
existing emission line models to arbitrary spin parameters of the Kerr metric,
no longer restricted to black hole metrics with $|a_\bullet |< 1$. We show that
the emission lines from naked singularity metrics ($|a_\bullet| > 1$) show
significant differences to their black hole counterparts, even for those
metrics with identical locations of the innermost stable circular orbit, i.e.,
emission line fitting does not suffer from the degeneracy which affects
continuum fitting approaches. These differences are entirely attributable to
the disappearance of the event horizon for $|a_\bullet| > 1$. We highlight some
novel emission line features of naked singularity metrics, such as ``inverted''
emission lines (with sharp red wings and extended blue wings) and ``triple
lines''. The lack of detection of any of these novel features provides support
of the cosmic censorship conjecture. We publicly release {\tt XSPEC} packages
{\tt skline} and {\tt skconv} which can now be used to probe the cosmic
censorship conjecture in Galactic X-ray binaries and Active Galactic Nuclei.
The inclusion of super-extremal spacetimes can be alternatively posed as a way
of stress-testing conventional models of accretion.
