accidentally left food in my hawkins contura for hours, now the inside looks darker and stained, is it safe and how do i clean it?

The darkening is from minerals in water or food residue; it's not harmful. For the Contura's hard-anodized interior, wash with hot water, mild soap, and a non-abrasive scrubber. Do not use abrasive powders, bleach, or dishwasher cleaning for the anodized parts. Dry it thoroughly after.

To prevent future stains, never leave food, water, or salted liquids in the cooker for extended periods.