The old shoes go from gray to their original blue color, without chemical additives but only with deep cleaning and neutral wax that returns the original color.
The products used are:
neutral Saphire beeswax (https://amzn.to/2HVgAO9)
horse hair brush kit (https://amzn.to/2uW8LVw)
leather cleaning solution (https://amzn.to/2VlQYBZ)
Relax and enjoy !!!