The unrivalled spatial resolution of the Chandra X-ray
observatory has allowed many breakthroughs to be made in high energy
astrophysics. Here we explore applications of Gaussian Gradient
Magnitude (GGM) filtering to X-ray data, which dramatically improves the
clarity of surface brightness edges in X-ray observations. In galaxy
clusters, we find that this method is able to reveal remarkable
substructure behind the cold fronts in Abell 2142 and Abell 496,
possibly the result of Kelvin Helmholtz instabilities. We present
results from our ongoing programme of analysing the Chandra and
XMM-Newton archives with the GGM filter. In the Perseus cluster we
identify a previously unseen edge around 850 kpc from the core to the
east, lying outside a known large scale cold front, which is possibly a
bow shock. In MKW 3s we find an unusual 'V' shape surface brightness
enhancement starting at the cluster core, which may be linked to the AGN
jet.