Ujssm question

[1965 wite]

When he talks about scooping the spent grains off the top and replacing with a equal amount of new cracked corn, what exactly does he mean? Do you do this after you add your water back to the fermenter or before? Is he talking about replacing all the spent grain or just the floaters on top? How do you know what is spent? After adding your water and backset back in do you need to restir aerate? I would think so but just want to clarify. I just started this recipe last night using fleishmanns bakers yeast. I have read that to reuse your yeast that you should reactivate at 110 F. Any truth to that? Thanks for the help. Looking forward to a ujssm with the duke boys from these parts.