The first rule is what not to do: balloons should never be released into the sky. What goes up comes down somewhere as litter, often in the sea or in the desert, where animals mistake it for food, and it can also interfere with aircraft. Nothing about a release is disposal.
For latex, cut the balloon open with scissors rather than leaving it whole. A cut balloon cannot form a loop or a pocket that traps a bird or a fish. Latex is natural rubber and does break down eventually, but it takes a long time, so it goes into general waste rather than being left outdoors to decompose on its own.
Foil is a plastic composite and behaves differently. Press a drinking straw into the self-sealing valve to let the helium out, and the balloon can be flattened and stored for the next occasion, since a foil shape can be refilled many times. When it is finally finished, remove the plastic valve and put it in the appropriate waste stream. Ribbons, clips and weights should always be separated, because loose ribbon is one of the most dangerous parts for wildlife.
- Never release balloons outdoors, indoors or over water
- Cut latex balloons open with scissors so they cannot form a trap
- Release foil gas through the valve with a drinking straw
- Flatten and keep foil shapes for reuse, since they can be refilled
- Separate ribbons, clips and weights before throwing anything away