Chitting Potatoes

Hi All, Help needed, I've stored my seed potatoes in a paper bag since Feb without giving them a second thought. Now it's come to actually chitting them they already have long white shoots about six inches long where they have tried to grow but been deprived of light. Do I break these shoots of and wait for new ones to grow, do I chit them with these shots on or do I just plant them as quick as I can?