We strongly recommend using a mattress protector to prevent damage to your Casper mattress (plus a protector makes cleaning simple—just remove and wash as needed). Check out the Casper Mattress Protector or Casper QuickCool™ Mattress Protector, both of which are waterproof and designed to shield your mattress against stains, dirt, and wear. Putting a fitted sheet on top of your mattress will keep it clean if you aren't interested in the protector, but it won't prevent spills or leaks from seeping into the foam.
Accidents happen. Spot clean any stains with a mild detergent, and then allow it to air dry completely before putting your bedding back on. Be careful not to saturate the stain with too much detergent.
For detailed product materials and care information, please refer to the label and care instructions attached to your mattress. You can also learn more about mattress cleaning in our Ultimate Mattress Care Guide.