In extreme cases you might need more, but we recommend starting with a regular bottle. You first use the Rejuvinator Oil to make the leather supple and bring dirt and contaminants to the surface, then you use the Prestine Clean to remove the dirt and maintain the condition of the leather. Prestine Clean is not a degreaser or heavy cleaner. It actually contains the mineral mica, very fine and powdery, in a base of non edible animal fat to loosen surface dirt and gently buff the surface clean without leaving harmful chemical residue that can break down stitching, or harm the leather. Leather should not be treated very aggressively as it was once a living thing.
Preventative maintenance is always better.
You will notice your hands repel dirt when they are moisturized with a good quality soap or lotion, but dirt tends to really find places to adhere when your own skin is dry. The concept is the same with leather. If it is healthy and in good condition it will not attract dirt. Silicone oils contrary to popular belief attract dirt. They do nothing for the leather itself.