It can be a bit challenging to clean due to its tough skin. Cut the squash in half with a sharp knife. If the skin is particularly tough, you may need to use a serrated knife. Scoop out the seeds and stringy flesh from the center of the squash. A spoon or ice cream scoop works well for this. If you don't want to eat the skin (though it's perfectly edible!) you can then use a vegetable peeler or paring knife to remove the skin from the flesh of the squash. You can also steam or boil the squash before peeling!