I worked on the treadle desk for a week or two before working on the sewing machine. So I turned the machine to the underside and got busy. I took a soft painters brush and cleaned out the heavy bits of dust first but a lot was still stuck because it was plastered in sewing machine oil but I did my best. Next, up I slathered it in Gojo and let it sit for a while, then started the process of wiping it off, reapplying and repeat, repeat and repeat it again. I used a lot of shop towels, Q-tips and scotch brite pads. Below is some before and after pictures of the underside. Before ...