I just rub gently with my fingers and if the scratch doesn't blend in I rub harder
As I mentioned earlier in the thread I had a bike hit my Birkin and there is NO visible mark now (after I jumped in a cab and rubbed it away). I also rub the bag all over with clean dry hands occasionally and if it gets a film I blow-dry it.
You CAN wipe Barenia if you actually spill something on it. Someone in my household
dropped a big blob of honey on my Barenia Bastia while it was on the kitchen island. When I saw it hours later, I used a damp cloth to take the honey off and it is fine. Obviously I can't guarantee this will always work but so far for me, it does for spills on Barenia.
If it's just rain or water droplets you can just let them dry naturally.