DIY leather cleaning?

Hello all,
I've followed this forum for a number of years. Have learned a lot. Hope this is the right place for this question.

I came across a H & M Weston Tobacco leather sofa, chair and ottoman for sale on CL (I posted ?? about value on the CL Furniture/ Attic Finds forum), The sofa has an area of discoloration that the lady thought was from her husband's head against that back cushion. So I presume that it is body oil that has gotten on the leather. Is removing this discoloration something that I can do with DIY products? Wasn't sure if the leather cleaner/conditioner, Leather Solutions, mentioned on this site would be able to handle a soil such as this.

Also she stated this was purchased in 1999. I know H & M are well built and it does look well cared for, but wanted to be sure of what to look for when I went to look at it in person. Would the cushions of a sofa this age have been eligible for the free cushion replacement. Wasn't sure if that warranty had always been in place. Was the Qualux filling used at that time?

Thanks for any help.

Once discolored from body stains it cannot be restored, short of replacing the hides in the affected areas.

Free cushion cores are available only to the original, registered owner.

I was not a dealer in 1999, so I can't say on the core materials.

Thanks for the info. I guess I'll just have to see how bad it is when seen in person. I was able to post some photos from the CL ad for these pieces in my post on that CL furniture forum. They're not real big, but may give an idea of the condition.