Drying and removing the balloon
To speed up the drying time, place the balloons in front of a heat source (a reasonable distance away). The process will take about 24 hours.
A tip for checking whether the paper is completely dry: Pull or push the balloon slightly. If it's completely dry, you'll hear little crackling sounds. This means the glue is definitely dry and the balloon can be peeled away from the paper!
You can now pierce the balloon while holding the knot, and then remove it. Close the hole by gluing a few pieces of paper over it.