Problem(s) Encountered:

Saturated the CCD during sky flats in both twilight and sunrise hours, resulting in ''icicles'' of saturated pixels on the top and bottom of the CCD.

I called cleansnap several times over the course of the observing run, and seemed to clear the CCD for the more important science frames.

Solutions:

The R4K is very sensitive to light.  It is best to err on shorter exposures and slowly increase exposure rates from there.  Note the instructions for twilight flats here:

http://www.astronomy.ohio-state.edu/MDM/OSMOS/#flat

especially the order of filters to use, and make sure you start with a very very short exposure (e.g. 0.1s) to test the sky brightness.