Now measure out the desired length of your dowel. I used about a foot-long section of dowel.
When you have measured and cut your dowel to your desired length, use a marker to mark where it will sit on the edges of the rim of the bottles. Then cut out notches in the dowel with your hacksaw. These notches should fit snugly over the mouth of the bottle.
To cut out the notches: Cut the sides of the notch, then make a cut in the middle. Twist the blade of your saw and the pieces should snap out. Also, make sure that the notches are not right at the end of your dowel so that cutting them doesn't break off the end.