I clean and condition my Barenia Birkin myself, and I've also sent it to Hermes. I am pretty happy with the results that I get at home using Lexol cleaner plus H Saddle Baum, but I feel like Hermes did a more thorough job of cleaning. It's probably because I'm scared to really scrub enough to get every single spot out, but obviously the craftsman is not.
I love the saddle Baum for conditioning, but with any conditioner, I am very careful not to apply too much on the handles and straps. I went overboard a few times on the handles because they seemed dry, and the end result was that the handles were softer, more bendy, and possibly easier to stretch if overloaded. The large panels are more forgiving if you get heavy handed with conditioner, although if you want an even patina, a very thin layer is much easier to control. I swipe my fingers across the balm so they get a bit oily, and that's the most I apply in any one spot.
