I've used Boeshield and WD-40. What you see in the pictures are part treated with WD-40. I use it to also flush out hinge joints and other tight spaces of "crud" that bead blasting and the very hot phosphate bath missed. The phosphate bath usually softens up the "crud" (it's an old US Navy term). When the WD-40 runs clear, it's clean (I hope).
Here's a series of pictures of tie rod ends I cleaned up.
Pic 1: As removed from a 66 Mustang "K" front end.
Pic 2: Cleaned. The finish at this point is "close" to what a factory installed, heat treated steel item should look like (minus the dirt).
Pic 3: Ball joint sealed with Permatex. It was an experiment. It worked. I let the Permatex "cure" for about SIX weeks. (Patience Grasshopper.)
Pic 4: Bead blasted. The Permatex kept the glass beads out of the ball joint.
Pic 5: Phosphated, The Permatex kept the phosphoric bath out of the ball joint. A "twofer". As the arm is hot forged, then dropped into a special oil (quenched). it should have a dark appearance with some scale.
Not shown is 90w gear oil applied drop by drop into the ball joint to "assist" in functional lubrication. Also, I used a Dremmel wire brush to give the steel base a more "realistic" look.
This was all done in April-May, 2013.
Jim