I speak from my own experience , and do not intend to conflict with any one.
You may try Leather Preparer to strip some colour , causing colour fade on the uppers. although Leather Preparer is very effective against newly put on pigment. It may not always work.
On Renomat and Renovateur , I don't believe that both will work. Renomat do wonders on colour stain, stuff that remains on top of leather and reflects . The thing that darkens your colour is called pigment, to which It can't do any thing. Renovateur, on the other hand, is a mild cleaner , only good enough for dust and so on . Plus its content , mink oil may also darken your shoes.
I would recommend you try Leather Preparer.
By the way, Collonil 1909 Leather Cream is similar to Saphir Renovateur, a gentle cleaner plus mild conditioner . It has Cedar Oil as conditioner , which doesn't do darkening.
Edited by SheenorShine - 3/31/13 at 5:55pm