I've been battling these scales for the last few months and lost one catt.
It was too late for that one. However, I was able to catch the scales on my second catt. I wiped the catt down with alcohol as much as I can. Then took the catt out of the pot and soaked the roots (up to where I couldn't reach the rest of the scales) in neem oil solution for 10-15 minutes. Thereafter, I repotted the (second) catt in new potting medium and pot. It's been two months (or so). I lost a few leaves and bulbs. But my catt is doing better...has new growths.
I just hope I've seen the last of those pests.