Hard to see them, I thought you were talking about the glands at first, lol. If the plant is otherwise healthy spray some neem oil on them, you can pick some up at your local garden center or lowes, spray at night or in the early am. Overall it's probably not neccessary, though. You could also try using a very very dilute soapy water solution and dunk the plants (also at night). Usually I spray em' down with a little plain water afterwards. If it's not doing any harm, though, just let it be or try picking some off with your fingers.