Is there a way to effectively & completely remove scale infestation from my
plants? I have lost about 80% of my orchids due to this pest. I also have 2
coffea trees that are just covered with them. I have tried multiple
applications of systemic on the trees, & spraying oils on the orchids, but
it only seems to slow them down for a while.

I'm getting to the point of just getting rid of all plants and starting
over.

Any advice would be greatly appreciated.
Sam