Yup, ACF50 is my weapon of choice! My last bike (WR250X) had been jet washed by previous owner. This seemed to have taken off the shiny coating, & the spokes needed ACF50 almost on a weekly basis during the salt season. They ended up black in colour,which I suppose is better than rust....
I also saw someone coat a rear wheel in wax underseal (I think), but this was a cast mag rather than spokes. Anyone here changed their spokes to stainless???