How do I remove these darkened patinas from this Louis Vuitton Popincourt Bag?

Picture #1, shows the contrasting color from the pale biscuit color of the buckle (probably) hidden away from body contact and sunlight.
The exterior suntanned color strip takes on a seasoned color would be the color of acceptance for a used bag.
The extreme “very dark brown patina on the corners of the bag (near the zipper)” is where the concern is.

Cleaning and leather rejuvenating ideally is to bring the appearance to the medium color range without the contaminated patina and the too raw unseasoned pale biscuit color.

Recommended process:

1] Patina Decontamination:
By Degreaser-2.2 > Rinse-3.0 > d’Tannin-3.5 > Hydrator-3.3 > Fatliquor-5.0 > Topcoat-59M > Protection-D+.

2] Seasoned Leathers:
By Super Cleaner-4.9 / Strong Cleaner-4.3 > Cleaner-3.8 > Rinse-3.0 > d’Tannin-3.5 > Hydrator-3.3 > Fatliquor-5.0 > Topcoat-59M > Protection-D+.

3] Raw Leathers:
Cleaner-3.8 > Rinse-3.0 > Hydrator-3.3 > Fatliquor-5.0 > Topcoat-59M > Protection-D+.

The above 3 levels of cleaning pertaining to the degree of soiling purpose is to balance the appearance of the leather holistically; besides preventing over drying that will eventually leads to cracks.

The cleaning and restoration can be accomplished with this Kit V3.tn with Topcoat-59M as an add-on.

http://i300.photobucket.com/albums/n...erkoh/V3BT.jpg
Leather Doctor® Kit V3.tn : Vachetta Leather Tannin Removal Kit

Any questions you have before we go into the details of the why; for the different level of soiling to even them out for a more acceptable aesthetic appearance.