This worked amazing on my Birkenstocks!  I washed the footbed of my Birks with a toothbrush and baking soda and the entire footbed turned dark brown. OH NO!  I was incredible disappointed and had only wished I could do a do-over. Searching the internet for a fix. I came across this brush.  I though...why not??  I can't make the sandals worse.  It arrived today and I used it on the footbed...brushed in circles..WWAAA LLLLAAAA...clean!  I have the results I had hoped to get with the baking soda. I am a happy customer!  If your looking to clean your very expensive Birkenstocks, this brush will do the trick.