^ Hi Leyla
No you will not have to pay - your bag isn't ready for a "full" spa service yet? - its simply a case of removing the marks. Just show the SA the white marks and explain how they have simply "appeared" on your birkin. If your SA is upfront and experienced, she/he will be familiar with this "problem" and will tell you about all the other customers who've had to get their bags cleaned -as this has been a problem with a lot of togo/clemence bags since beginning of 07. Hopefully, they will try and rush the job through.
I'm currently in Paris and the turn around for me was pretty fast. I am still slightly concerned that after the 2nd cleaning the marks are ghosting up again!
However, unless they become very apparent, I plan to hold off bringing my bag in again until I have a buyer for my apartment and know when I will be leaving town (hopefully, in the not too distant future!). I don't know whether or not they can clean in-house in London or any of their other stores or whether all bags need to be sent to the Paris atelier for this.
Please do let me know what your date stamp is?
thanks!