ScarletTricycle said: I did two things this year.
I used a sharpie on a cleaned tuber and then I toss mine w cinnamon. I roll the tuber in Saran and then tuck in a cutdown notecard written on with sharpie as I roll and wrap. Works well for me. A lot of the commercial growers tattoo/stamp the tubers with names which leaves them w the fine blue names.
Kristine Albrecht from Santa Cruz is using surgical markers on hers as the markers are used on skin and a softer tuber can handle it. I did have some issue w the skin lifting on a few of my tubers.
Hope this give you an idea.