Two things that have worked for me:
Green anoles (baby) if you can find them, live. My greyband went crazy for these. Be careful, though, as they can injure the snake. I paid my little brother $1 a piece to catch them for me to keep my snake going until I was able to switch him to pinks using the method below.
Rather than scenting a pinky, de-scent it. Rub some Ivory soap in your hand and roll the pinky around in it to wash off the scent. Then rinse thoroughly. You may have to combine this with the split brain method and leave the mouse outside the snake's hide box. Eventually I was able to stop washing them.