I just acquired a set of the pens. So far, so good. I've found that Oxy Clean works well at bleaching out stains without the harmful effects of bleach. I'v used it with detergent and a very gentle cycle in my front loader on an antique which came out looking fresh as a daisy. Perhaps it would work on your lines. The few times I've used the pens I've always used the steam iron. Perhaps that's why I haven't had a mishap.
I'll be following this thread.