Spray them off with a heavy stream of water or you can scrape them off and smash them.
Mix a couple of tablespoons of original Dawn in medium sized bowl of water and wash each leaf. Check stems, too.
cheap dollar store light green liquid soap and apple cider vinegar
1/4 cup soap 1 cup vinegar. Pour into shallow container and set among plants. By days end they dead. Change out every couple days
I have to spray my large maple tree with liquid blue Dawn mixed with water every year. Repeat in a day or two if necessary. 2 1/2 Tablespoons per gallon of water and remember to spray under the leaves.