Abstract: A reusable packaging bag for fitting around an article and a method of using the reusable packaging bag. The packaging bag comprises an air-porous plastic bag which contains a plurality of plastic particles of different sizes. One or more of these packaging bags are fitted inside a container and around the article to be packaged. When the lid of the container is closed, some of the air inside the packaging bags escapes thereby allowing the plastic particles to be fitted together in a substantially rigid body which molds to the shape of the article between the interior of the closed container and the article.