(1) The Bais Yosef brings two reasons for the primary rinsing, a) The Rosh holds it is for any blood that might have dried on the surface because salt will not absorb dry blood that is on the surface of the meat, b) The view of the Ran is that the washing is to soften the meat, making it easier for blood to escape during the salting. The Hagos Maimoni gives the reason that it is to remove the blood that is on the surface of the meat, for otherwise the salt will simply fill up with blood and not perform its function of removing the blood that is in the meat.
(2) It seems that the butcher would have to soak the meat in water in order for it to be sufficient. A small spraying of water is insufficient.
(3) The hooves.
(4) However don’t let it totally dry because then the salt won’t stick to the meat and won’t bring out the blood.
(5) The reason is because we fear that the vessel was not cleaned properly from the blood, however post facto the vessel is permissible.
(6) However if there is a sixty ratio of water against the meat, the meat would be permissible, because even if it was cooked without being salted we are lenient in a case of great financial loss. Therefore, we would permit the meat even without incurring a great financial loss as long as there was sixty. The Rashal disagrees.