If high pressure washer( OVER 3000 PSI) is not available you going to have to scrape all that "muck" off first. Sand would require plenty of product because it bounces off the muck until slowly wearing it down. Diesel is a good degreaser depending on your location. Oven cleaner causes problems with any aluminum parts.
I'm not really sure if I'm going to keep it for now or not. Haven't lost motivation for the project I just don't have the time anymore.
If it was a pete we would be talkin cash right now. And i feel ya for not enough time. I have 2 tractors to spilt, a harley to put together, a basement to redo and 2 or 3 projects for " when i get time"
Put it on kijiji with a price and test the waters. Not worth much at all in pieces, there’s a butt for every seat You should sit on it until you have time. My frameoffs each took 3 years. My neighbour spent 20 years to complete his frameoff.