After a long cookie baking session, you might be tempted to throw the cutters in the sink and deal with them later. But trust us, you and your cookie cutters will be happier if you wash them promptly (or at least keep them dry until you do) and then ... pop them in the oven!
Metal cookie cutters should be gently hand washed and then quickly dried to prevent rust. To ensure that all nooks and crannies are dry, place the cookie cutters on a clean baking sheet in a warm, turned-off oven for a few minutes.
There's also the blow-dryer method, but most of the time the oven is already warm from baking, so it's easy to pop the cookie cutters in. A toaster oven may be used, as well.