This is fabric crocking. I had it happen once with red fabric. I tried lots of different solutions but it eventually wore off with continued sewing. The next time you go to sew a colour saturated fabric, you might cover the machine bed with Glad Press and Seal to prevent crocking. As for removing it I would try alcohol, hair spray, peroxide etc. on a small area to see if it with lift the colour but not harm the surface of the machine.