The internet abounds with untested, and potentially unsafe, recipes. In the sun-pickle recipe, you fill a quart jar with cucumbers, add salt, and then fill with cold water. The lid is placed on the jar, and tightened, and the jar is allowed to sit in the sun each day until the water turns from clear (at the start) to cloudy (in the middle of the process) and then clear again (at the end). According to the recipe, when the water becomes clear again, the pickles are ready to use.
This type of recipe is not safe. This recipe presents a risk of illness linked to three major foodborne pathogens: E. coli O157:H7, Clostridium botulinum, and Listeria monocytogenes.
Read more here: http://fyi.uwex.edu/safepreserving/2013/09/13/safe-preserving-sun-pickles/