Is the machine computerized? If not, I would suggest one of those magnet wands. If it is computerized a magnet is a big No No! Do you have a set of hemostats that could reach it. Hemostats are those long skinny plier like things that are handy in the sewing room. How heavy is your machine? I might try tilting it up and hope it rolls out. I don't have a Janome so I can't offer any more advice.