Just read an interesting thread over on a Jeep forum. They have some data to back up a really cheap solution...50/50 acetone & ATF. Worked twice as well as Kroil according to the test. See it here...
Home made penetrant http://www.jeepforum.com/forum/f7/best-rust-penetrant-ever-you-make-yourself-552838/I plan on giving it a try. Lord knows I have plenty of 66 year old rusty nuts, bolts and screws to try it out on.
