You usually see “Wash Me” written on the back window of an extremely dirty car, right?  A dirty car is a eyesore but dirt on a plant actually affects its health.  In their natural environment, plants are routinely cleaned by wind and rain. But when we bring plants inside the house, it is up to us to give them a bath.  Why take the time to do this?  Leaves dirty with dust, grease, and other nasty stuff won’t absorb as much sunlight as leaves that are clean and this affects their ability to photosynthesize. Wash your plants every couple of months using a soft cloth or sponge and warm water. If you have a lot of houseplants, group them in the shower and gently spray away!