I've never left it in direct sunlight, but I have left it outside in the shade, with a nice breeze it takes about two hours. A better way to go would be boil up a pot water put it outside and place your container in it. The heat from the water and the breeze outside should cut down the time to about 30-45 mins.
Remember it also depends on temp\humidity outdoors, how much ISO needs to be evaporated and % of the ISO used).
Bookmarks