I've been fighting scale for awhile, but on cattleya. My methods might kill a phal because I have to completely dunk mine in a chemical mixture...neem oil, murphys oil soap, and anything else I can think of to throw at them! I leave my plants totally immersed and then go over them with a toothpick and toothbrush. The toothbrush removes all the old stuff off of p-bulbs. Toothpicks get into the hard to reach places. Of course, again, this is for Catts. I haven't ever had scale on my phals...yet.