Put it in the washer, use hot water and a little bleach. To balance the machine, put in an old towel. Run on a regular cycle.

SG

I never thought of that!

I put chlorine on the mat
and lay it outside in the sun.

CDO

I put my bathmat in the dishwasher recently, and it came out pretty clean except for a couple spots of mildew. I attacked them with a wet soapy washcloth. It looks like new!

I thought bleach should not be used on rubber as it breaks down the rubber?