Cut the guavas into cubes, taking out the seeds and all.
Place a large skillet over medium-low heat and add the guavas with the sugar and salt. Cook for about 20 minutes, stirring occasionally, until the guavas are soft.
Let the guavas cool for 5 minutes, then place them in a food processor or blender and process and puree until smooth and free of lumps.
Place in a medium bowl with a strainer and strain the guava puree to remove the remaining seeds or any existing lump.
Add the lime juice to the guava mixture and mix well with a spoon.
Pour the mixture into an ice cream container or a bowl with a lid and freeze for at least 8 hours for the sorbet to form.
Remove the sorbet from the freezer 5 minutes before serving to soften slightly, and it is ready to eat.