The methane filter is narrow, centered on 889 nm. Features that are bright in methane images are typically found at high altitudes where light is reflected before it is absorbed.
This is the filter bandpass:
Here is a nice image of the south polar hood:
We have a source of stray light that causes bright artifacts in the images. Those portions of the images are saturated, but other areas in the image are fine and can be used for analysis.