The reason that I reccomend SOS pads is that the soap has a compound that helps prevent pitting and corrosion. If you use just steel wool you're basically just removing the existing rust and byproduct of the pitting... The SOS pads will help neutralize the pitting and corrosion.

Like you said though, don't use a lot of water. I suggest having a dry towel and a damp towel and dabbing the SOS pad on the damp towel... Cleaning one fret... then drying the fret with the dry towel as you go. Never let water sit on your fretboard... That's why I suggested the masking tape.

Either way you should get some clean frets though.