I would have used a spark generator had I thought of it earlier, but the fan trick worked for me. I play on the Wii U so I could monitor it on the gamepad while watching TV. Up to 45 minutes per figure. I got the through them all pretty quickly.
I feel a little dirty for doing it this way, but I figure it's the game's fault for not having any real incentive to level characters up much earlier and perhaps in a more legitimate way. That's my story at least.