honestly though, this works according to a foot doctor my mom went to. this goes for ANY shoes, not just sandals.
If you are going to get the smell out of NORMAL shoes, first take the sole out of the shoe. Sandals obviously don't have them. Then get an airtight bag and pour baking soda in it. Next put your shoes in the bag as well and seal the bag shut. keep it in there for 24 hours atleast. then when you take them out, wash the shoes.
the doctor claimed it will get all odors out of the shoes. you should try it w/your sandals.