The program seems to reject most of the bad reflections that have interference from ice. But still I see big peaks in the R-factor distribution printed in Scalepack where I see the ice rings to be. What's the best way to take care of ice rings?
It is done automatically, however one can adjust reject fraction parameter to improve the accuracy of the rejections. Default value is 0.75, increasing it to 0.8 - 0.85 may help. Look at the display to see how many reflections turn red.
We got really bad icing on a couple of frames. How do we leave them out?
You can omit whole frames from scaling, or use resolution limits to avoid ice. In the extreme case you may reprocess the same image twice with resolution ranges below and above the ice rings.