How do you keep faux olive trees clean?

Yes, but if you think about it, real plants get dusty too. I try to take my Swiffer Duster to the leaves once every other week, but if there’s one that has serious dust, I use Nu-Leaf Artificial Plant Cleaner. You simply take your plant outside, spray, and let drip dry. Clean as a whistle. If you don’t mind using an aerosol, try using this silk flower and plant spray or this one that is unscented. Both will add an extra level of dust protection to the leaves.