Here are basic guidelines for treating stains on leather clothing, shoes and furniture, and they apply to all gradations of the material. However, cleaning can alter the color or appearance of leather, so when in doubt, consult a leather-cleaning professional.
Mildew stains. Mix 1 cup (8 fl oz/250 ml) rubbing alcohol with 1 cup (8 fl oz/250 ml) water. Moisten a cloth with the mixture and wipe the affected area. Leave to dry.
Ink stains. Spray the affected area with hairspray, then wipe it off with a clean cloth. Ink can be extremely difficult to remove, so you may need to consult a leather-cleaning professional.
Water stains. Allow a soaked leather garment to dry slowly and naturally. Keep the item away from heat sources, and restore its softness with a leather conditioner after it's dry. For soaked leather shoes, insert shoe trees and let air-dry.
Grease stains. Blot excess grease with a clean cloth. Sprinkle talcum powder or cornstarch on the affected area. Let sit for at least 4 hours, then wipe off the powder.
Protein (Blood, Urine) Stains. Blot excess moisture with a clean, damp cloth. Allow item to dry slowly, away from a heat source.
Gum. Rub with a plastic bag of ice cubes to harden the gum, and then pull off the gum. For any residual gum, heat the area with a hair dryer and rub off the gum with a clean cloth.
Salt Stains. Mix a solution of 3 parts vinegar to 1 part water. Moisten a cloth with the vinegar solution and dab on the affected area.
Discoloration. For leather garments, gloves and bags that are discolored, use a leather spray designed to restore color. These products are sold at shoe repair shops; choose the color that most closely matches.