When I got my treadle, the man I purchased it from told me once I got it home to sit it on newspapers and spray the heck out of all the bottom metal work (stand & treadle) with WD-40, let it stand for a few minutes, then scrub with a soft bristle brush. He said this would clean the metal and protect it from rust. I did what he said, and it turned out so nice. The decalling on your Sylvia is beautiful. She must have been dearly loved to have been taken such good care of.
I actually bought my treadle so that I would be able to sew during power outages. I also have a battery powered OTT light and a battery powered fan. We were hit by Hurricane Ike about 5 years ago, and I didn't have electricity for a week, but I was still able to sew. LOL