After purchasing a second Juki to go with the mid arm frame I bought, the woman I bought them from gave me a few tips - among them was how to clean the Juki. It has a small lid that you can remove to clean a portion of the underside of the machine, but what no one tells you is that you can remove the screws and take the whole bottom off.
I've got a before and after photo for you to see.
For the first time, I had DH help me, but it certainly can be a one person job. I vacuumed and brushed out the whole underside; put the bottom back on...and done!