Examples of continuum-model fits for a pair of spectra (SDSS-I/II in the upper panel, BOSS in the lower panel) where we observe C IV BAL disappearance. The red line represents the signal as a function of the rest-frame wavelength, while the blue regions indicate the RLF windows used to fit the continuum model, which is shown by the solid black line. Vertical dashed lines indicate rest-frame wavelengths corresponding to features that are typically seen in QSOs. The source ID in the SDSS archive, together with its redshift and information about the plate, MJD, and fiber corresponding to the observation, are also reported on top of each panel.