While picking out hooves, STAY AWAY FROM THE FROG ('V' shape in the hoof)!
I guess we'll have to agree to disagree here. :)
You always want to clean that area. It is the place where thrush most often happens and it is very important to clean it out. Make sure you get all the dirt and manure out, and don't be afraid to go all the way to the bottom of the frog.
If there is thrush there, the original amber-colored Listerine sprayed on it will kill thrush without damage to the hoof, unlike bleach water.
**I must not forget to thank the difficult horses, who made my life miserable, but who were better teachers than the well-behaved school horses who raised no problems.**