Close your blinds so they sit flat against your window. Your blinds come with an adjusting rod or rotating drum that makes them open and close. Rotate this to close your blinds fully so that you can target one side of your blinds.If you retain your blinds open it is going to be tougher to clean either side of the wood slats. Use the brush attachment in your vacuum to remove dirt between deep cleanings. To hold your blinds clear, and your exhausting efforts final, sweep or vacuum the blinds in your house regularly.