Citrus fruits, as with many other fruits and vegetables, are sprayed with a wax to keep their skin gleaming and fresh-looking. While the waxes are considered "food safe," it is never desirable to ingest chemical compounds when unnecessary. Washing and scrubbing of even inedible fruit peels is recommended to remove waxes, trace ground soil, microbes and latent pesticide products before peeling or cutting into a citrus fruit.
Hold your citrus fruits under a cold running tap in the sink to rinse the skin.
Scrub the entire surface of the citrus fruit peel with a vegetable brush reserved for use on your edibles and not commingled with dish-washing brushes or scrubbers. Hold the fruit under the tap as you scrub to wash away the loosened debris.
Rinse a final time after scrubbing and before sitting the citrus fruit out on a clean towel or plate to dry.