Check out an automotive leather kit. They are great for this type of leather issue.
Depends on the current status of your leather. I have used saddle soap on automotive leather as well as a chair we had. Smells good, cleans, and conditions. Use it with a little warm water and a brush. This is what I've used: https://amzn.to/2ZY9Nes
Hi Donna, you didn't say what leather, so I hope this helps you out
Is this for a car's interior, a jacket, shoes, a piece of furniture or what?
Use a leather cleaning product. Saddle soap also works. If dull, the leather may need a reconditioning product made for leather.
Hi Donna: Check this site: https://www.wikihow.com/Fix-Scuffed-Leather I've used the petroleum jelly on a few things and it worked for me. Good luck
Where is the leather?