what can I use I have read a lot of remedies but I am not sure which one is really the one to use
Boots are boots. They're meant to get oil on them. If only one has oil on it, then purposely spill a little on the other. I did that with paint, and now my Brahmas match nicely.
Put a little bit of dish soap on a the stain, then wait about half an hour and give it a good scrubbing with a toothbrush.