Pick a squash that is rock solid and heavy for its size. Its skin should be matte. A shiny finish is a sign that the squash wasn’t ripe when it was picked. Look for an intact stem, which will help slow down the loss of moisture.
Rinse squash under cool clean water to remove any remaining dirt. If needed a produce cleaning brush can be used. Do not clean squash until ready to be used.
Protect butternut squash from light and heat by storing it in a cool, dry place. If it is a whole squash do not place in the refrigerator. Stored properly, a whole squash will keep for a month. A cut uncooked piece wrapped in plastic will last for up to 2 days in the refrigerator.