Stain spots on passenger-side door
 

I was cleaning my 2011 ES350 today, and I noticed there were these stain spots on the interior of both passenger-side doors. See below:

https://cimg9.ibsrv.net/gimg/www.clu...0f6f1fcb70.jpg
https://cimg1.ibsrv.net/gimg/www.clu...aac4edbb97.jpg


I tried cleaning with water + micro fibre cloth, but doesn't seem to do anything. Does anyone else have this problem? I don't see it on the front driver side, but some much faint residue that's similar on the rear driver side

I'd like to think I keep my car in good condition and its not like food grease or something. Any idea what this is?

It can be engine oil or brake fluid.

Try to clean it with leather cleaner.

Looks like some sort of grease or oil. Try a leather friendly anti grease product.