I propagate and raise Gardenias, Christmas Cactus and Jasmine in the greenhouse and I have several other stock plants of the aforementioned as well as other tropicals in my home and my bird room.
I have had both mealybug and aphids and since it would be a never ending task to wash them with the alcohol I take them outside (if the weather permits) or put them in the slop sink and spray wash them with plain water. When I get the worst off them, knowing they are tricky little devils, I spray with a mix of Dawn, Water and Neems oil. Top and bottom of the leaves and all the stems. It works very well and is natural. I can not spray anything inside because i have several parrots. I also pour some on the soil and around the pot top and bottom after washing them with the water.
My problems will start all over again when I bring in the plants from the outside prior to frost. If it happens in the greenhouse, I do the same thing as I do with the houseplants. A good washing and spraying.
You may have to spray a few times before you get them all in the event you missed some during the washing. This is what works for me since I do not have a lot of time. I am required to have my greenhouse inspected once a year by the State in order to be a Certified Nursery and ship starter plants all over the USA. The Dept. of Ag. inspectors also suggest the mixture I use.
This may help those of you who have a problem with the stronger sprays. Have a great Day.