Silicone. Clean the surfaces with a little alcohol first. Should stick tight but be removeable, too.

thanks asolo - what specifically should I get - is it a tube of silicone caulking or just plain silicone? Is there something specific for appliances?

General catagory is "silicone rubber sealant". There are a number of different brands....Dap, GE, others....available typically in 2-3oz tubes available at any hardware store. All will serve well for this purpose. I suspect you'll find it easy but if you mess up, you'll also find it easy to re-do it. The secret is getting the surfaces clean. Adhesion will be adequate and long-lasting but still forgiving if/when the time comes that you want to replace or re-do.