Provided are a washing method, a washing device, a storage medium, and a washing composition for enabling effective removal of a treatment layer by decomposing or degenerating the treatment layer at a higher temperature than conventionally. According to the present invention, in a state where a substrate provided with a treatment layer is heated, the substrate is supplied with vapor of a component (A) that can decompose the treatment layer, and thereafter the treatment layer that has reacted with the component (A) is removed from the substrate. As the component (A), a nitric acid or a sulfonic acid is preferable. As the sulfonic acid, a fluorinated alkyl sulfonic acid is preferable.
