Photo 1: Starting at the tapered end of the strawberry, push the straw through the strawberry.
Photo 2: As you are pushing, keep the straw centered so that the end of the straw comes out of the middle of the stem.
Photo 3: The straw has captured the pith, cap and stem. Remove the stem from the straw and remove the straw from the strawberry.
Photo 4: Some of the pith may remain in the straw. That is fine. When you are done hulling the strawberries, just rinse the straw under water and it will likely remove the remaining bits. Also, as you are hulling strawberries, some of the pith will naturally be pushed out the other end.
Photo 5: I had half a Costco carton full of strawberries that I knew I would not finish before they go bad so I hulled the strawberries and placed them in a freezer bag to freeze. I can use them later for breakfast smoothies.