I've used WD-40, alcohol, white spirit and acetone the last few hours. As well as a brass brush on the fork surface rust. Starting to look pretty good and while there are endless scrapes and cable rub everywhere I've not found any dings or cracks!
Something oil dissolving like benzine is probably going to more efficient than spirits and acetone, but keep up the good work. Looking forward to see the build!
Get some isopropyl alcohol / disc brake cleaner!