Use gojo hand cleaner (try it first on a hidden part )
The best way to remove motor oil from leather is to use leather cleaner. You can also try to use Oxy-clean.
The best way to clean black leather is to vacuum and dust with a dry rag. For deeper cleaning or to remove stains it is best to follow the manufacture's instructions as there are different kinds of leather requiring different kinds of care.
Do it while it's still hot and soft. If it's set, you're SOL.
The best cleaner is the classic soap and water. This is a cheap and very effective way to remove any stain or substance from leather.
The new car smell is caused by products used on the leather to clean and preserve it. It is a part of the leather or vinyl. The best way to remove it is to open the windows and allow it to air out. It will fade with time.
The best way to remove oil stains from leather is to use a smoothing iron and blotting paper.
Warm, soapy water is the best way.
Best way to break-in leather boots is to wear them!
To remove tar from denim pants, you can place the affected area in the freezer to harden the tar, then scrape it off with a blunt tool like a butter knife. Next, apply a stain remover or a mix of dish soap and warm water to the spot, and launder the pants as usual. Repeat if necessary until the tar is fully removed.
Buy a leather care product such a Mothers Leather Care.
The only way that tar can be removed from lungs is over time. Unfortunately, if you have been smoking for many years, some of the damage is permanent.
The best way to clean leather briefcases is to use specialist leather cleaners. Autoglym, Renapur and Astonish are all producers of these products and all can be purchased at Amazon.