Halliday & Matthiessen (1999: 208):
Some qualities can be construed as processes of doing; here for example there is an agnate form I've dried the plate, with 'dry' worded as a verb. In these cases, the quality is not repeated as an Attribute — we do not usually say I've dried the plate dry; it may however reappear in an intensified form, e.g. I've dried it very dry. Very many qualities may be construed as verbs in this way.