There are three principal forms of conditioner: 

1. Conditioning Creams: These products nourish and moisturise and cause minimal colour change. A good conditioning cream will keep the fibre supple and provide some protection to the surface of the leather.
2. Conditioning Oils: Neatsfoot oil and lanolin have been used to soften leather for centuries. An inappropriate oil will make the leather sticky and may even cause it to become rancid.
3. Wax Conditioners: Wax will not penetrate deeply and nourish the fibres but it does provide an excellent surface protection from water and other liquids. 

Wet leather needs to be treated while it is still damp, it should not be allowed to dry out. Applying leather conditioner to the damp leather enables the product to seep through the pores and into the spaces left by the evaporating water. If not treated, it could result in leather cracking.

Leather will be stained by water, especially rain. Stains can be removed by rubbing the spot with a clean, damp sponge. Allow to dry naturally, never use heat to speed up the process.

Wet leather could shrink because the water displaces the natural oils and leaves the leather fibres exposed to the air.

The following products all achieve four and a half stars out of five on Amazon customer reviews:

1. Leather Nova Conditioner and Cleaner
2. Leather Honey Leather Cleaner
3. Lexol Leather Care Kit
4. Chemical Guys Leather Conditioner and Cleaner
5. Meguiar’s Gold Class Rich Leather Conditioner and Cleaner

• Leather peels because it has become dry as a consequence of the absence of its natural oils.
• Leather smelling bad: Leather is a porous, natural material and consequently it can absorb smells such as perfume or smoke. 1) pack in a newspaper 2) Clean with equal parts distilled white vinegar and water 3) Sprinkle baking soda then place in a sealed container for 24h then clean with a dry cloth.
• White marks occur on leather because of water damage, damp or because of salt staining. They can be removed by applying polish, in the case of shoes, or leather conditioner for other items.

Sticky deposits on leather should be attended to as quickly as possible. Dab immediately with a clean cloth, don’t wipe, this will only make matters worse. Apply a leather cleaner lightly and remove any surplus with a clean, dry cloth. Allow the leather to dry naturally and then condition.