Sky-subtraction workflows for KCWI-red (left) and KCWI-blue (right) observations. Both channels start from DRP-produced data cubes (after WCS correction and spatial cropping), which contain a mixture of sky background and astrophysical continuum emission; KCWI-red data additionally include significant CR contamination. For KCWI-red data, sky subtraction and CR identification are performed iteratively. A temporary sky subtraction is first applied to produce a cube used for CR detection. The resulting CR masks are used to refine both continuum and CR masks, and the process is iterated until stable masks are obtained (typically two iterations). The final sky subtraction is then performed once using the refined masks. For KCWI-blue data, CR contamination is substantially less severe and is generally handled adequately by the DRP, so only continuum masking is required. A temporary sky subtraction is used to identify continuum sources, followed by a single final sky subtraction using the refined masks.