As vegan leather is made with a plastic coating, it is already waterproof. This makes it easier to clean by using a mild detergent or just by wiping it with a damp cloth, however it also means that conditioning products can’t penetrate it to stop it from drying up and cracking, which can happen if the fake leather is in the sun a lot and also if it’s a particularly poor quality material. However, you can get certain products, which will cover the surface of the plastic to prevent high temperatures and sun rays from cracking the surface. Such products can also help to soften the material.
For the product made of vegan leather, such as notebook, diary, or padfolio, just use a wet cloth to wipe the cover.