I'm pretty excited to report some success I've had with ink on a white bag. I neglected to take a picture of the ink mark before I did anything. The first picture is after the first treatment. It was a lot worse before that. I put that on before I went to bed so no sun exposure. After the second treatment, I put it in the sun for about an hour. I don't know if the sun helps. It seems it worked some without it.
I got the idea from JaNan16. Here is her original post: http://forum.purseblog.com/showpost.php?p=27876836&postcount=7645 It's on page 510 of this thread.
Impressive!