Leather
Cleaning
Firstly, leather is highly absorbent which means that any oil or dust will stick to it, so make sure to keep your hands clean while handling it.
Next use a soft brush (horse hair or a soft cloth) to remove any oil or dust. This should be done regularly to refresh your leather pieces.
Another thing you can do is use a leather soap. Choose the right one for your leather type (genuine, treated or untreated, suede) and read the instructions carefully. Usually washing it with soap includes gently wiping and cleaning in circular motions with a damp cloth. Then wipe the leather dry with a clean cloth to remove all soap and water residue. Finally, let your leather air-dry, since any other way would dry out and damage the leather.
Some leathers can be gently washed in the washing machine using little soap but vintage leather is advised to be kept out of it, since it could easily dry out.
Conditioning
Using a leather conditioner regularly is important because leather dries out over time. After dusting of the leather, apply some conditioner on a damp cloth and apply it to your leather. If there are damaged areas make sure to put conditioner on them as well.
Storing
During off seasons, store your leather in a dark and cool place as hot temperatures and sun exposure can dry and fade it out. Some items should not be hanged for long period as well as they can stretch out and lose shape from its weight.