I guess this was a custom unique to Hanamachi (花街, districts where Maiko and Geiko reside and work)...
When we Maiko wore new a Kimono (着物) or an Obi (帯, belts for Kimono), we used to make a wish, "Please let me keep this Kimono clean without any stain or smear by food or dirt", holding them high with both hands and bowing deeply.
Speaking of Kimono, I remember one thing that I was often told by my mother and grandmother when I was a child. When I made a rip or a loose end on my Kimono, they used to tell me, "Say the Omajinai. Say that you already took your kimono off!" As soon as I said it, they repaired the Kimono as if nothing happened.
In fact, I still don't know how the Omajinai works. Repairing Kimono while the child is still in it is dangerous, and I guess it was considered to be ominous. My mother and grand mother must have been trying to turn a blind eye to those inconveniences. Today, I say the same thing to my children. In Kyoto, various kinds of Omajinai still remain.
Click here to see a Blog by a Former Maiko, "Do You Know?".