At least you have a mill, I've been scraping mine in...
I've tried sandpaper wrapped around a round backing with good results, but very time consuming. An option I'm looking into is EDM stones, I feel these might be a better solution, the next time I do a fuller I'm planning on trying them. Depending on how wide the fuller is, a small wheel might be a good option.
http://forums.dfoggknives.com/index....Bedm+%2Bstones