A couple of weeks ago I cut some of my oregano and rosemary and hung it to dry, some I hung and the rest I place on dehydrator trays to dry.
I remove it from the stems and put the herbs in my coffee grinder, it just takes a second or two and it is ground.
I did not make a green smoothie but my fingers were getting very green. To remove the stem I have always either rolled it in my hands or grab the stem and run my hand down it.
My fingers look like this after scrubbing with a brush and dish soap. Then I had a "moment" I got the pan that I deep fry with, it has two size holes in it, I used the smaller holes. I took enough of the rosemary off of the tip to expose a 1/8th inch of stem, then stuck it in the small hole and pulled it through. This was faster and cleaner.
I ended up with 2 jars of rosemary and one jar of oregano.
The best smoothie that I have ever made was not a green smoothie. It was a pink smoothie, made from dragon fruit.