I was afraid to dunk it because Kooba was an unfamilar brand and because it was a light color and made of Italian Lambskin, which sounds delicate; but it was so dirty and there was ingrained grimy areas, especially on the back and bottom of the bag, and also some pen marks.
I started out by doing a quick, gentle sink bath in Dawn soap suds and water. I gently rubbed the worst areas and then quickly rinsed the bag in clean water and arranged it to drain in the sink.
It held up well to the bath but it was soon obvious that the the dirty spots hadn't improved much, so it went back for a longer bath, and the second time I gently scrubbed the bad areas with a soft fingernail brush and Dawn soap.
The Kooba leather bag held up well to all of this rough treatment. But when it was almost dry I realized that the leather was very dry so I moisturized it 3 times. First, I applied Leather Therapy Restorer, then Leather CPR, and finally Black Rocks Leather n Rich. I let the bag "rest" for a day or two between applying conditioners. Then I brushed it with a soft horsehair brush after conditioning and I buffed the hardware with a soft cloth.
Like I said, the Kooba bag held up well and I am glad that the leather has darkened a little, but you never know how a bag will react until you try it.
If it is an expensive bag (or a rare or delicate bag) then I find it more difficult to give it the "full rehab treatment!" but if it's so dirty that I can't wear it, then I usually find myself "going for it!" It usually works out okay, but not always!
