Timing is the key when one tries to manage scale of any kind. The following statement from the UC link posted above states the two CRITICAL factors as to the time to spray: "If scales become too numerous, a well-timed and thorough spray using horticultural (narrow-range) oil applied either during the dormant season or soon after scale crawlers are active in late winter to early summer should provide good control." In other words: 1. dormant spray 2. or when crawlers are present

I suggested that a better picture might result in a 'which kind of scale' identification. And it does! That's the wax scale, VERY common on hollies and a wide range of other woody plants. A quick search on 'control of wax scale' will lead to some suggestions to get this infestation under control.

Looks more like traumatic damage and NOT scale. The spots could be from sun. The jade is common jade that is dry but should perk up once it grows some roots.

I haven't posted on this forum for a long time but did have experience with scale on an Adenium that was gifted to me. The previous owner couldn't get rid of the scale so she gave it to me instead (I told her I'd try to save it). I did use rubbing alcohol with a cotton swab to remove any visible scales. But as Rick said, it is not a cure. More soon emerged and I went the insecticide route. I use Bayer's Advanced 3-in-1 Insect, Disease, and Mite Control. You can use the ready-spray version or buy the concentrate and dilute it yourself. I sprayed it 3 times, 10 days apart. Make sure to coat the top and bottom layer of the leaves plus the trunk. The scales had never come back and it has been 3 years. Good luck to you!