This salt can come from tanning process, from perspiration or from the salt they put on the streets...
Put a wet cloth over the salt stain area for a few hours. Apply Urad while still wet and let Urad work. When dry, Urad will have worked the salt up and out of your leather to the surface. Gently rub it off with a soft dry cloth. If needed, use Aquila to remove any salt remaining. Apply Urad again.