I thought I might discuss the whole "Drop it," idea. Let's face it, dogs may pick up and chow down on the strangest things around, and the most gross things of course. Once an item is inside the dogs mouth it is one hundred times harder to get it out. Stop the behavior before it happens and your a champion, get a dog to spit out something they want to eat? You are a star my dear friend. The most common cause of dogs picking up items is us; that's right we have associated attention to picking up unwanted items. So the first step is self control, our self control. No chasing, screaming, arm waving etc if your pooch picks something up.** Many dogs just simply pick up the taboo item and wait for you to fly into action. Others chomp and swallow, these are the very dangerous situations so training needs to be done now.
You start out by teaching your dog what "drop" means. So; when they have a low value item, something they are allowed to have you begin the training with that. Walk up to them and say "drop" while holding out a very yummy treat. They may smell the treat and keep the toy in their mouth, if they want the food enough they'll drop the toy. Praise and reward immediately. Give them back the toy. What you are doing is creating the association of dropping items out of the mouth = receiving food. You need to work up to the point of just saying "drop" without holding out your hand and having your dog drop the item. Always reward. You can sometimes reward with another better toy but never take away the original item.
Then you up the value of the item, perhaps a brand new toy. Approach your dog, say "drop" and reward with an excellent treat for dropping. With enough practice, an automatic response starts to take place. As you up the value of the items to be dropped you are training for that big moment when you really want the item. By not taking away the items from your dog you are lessening the impact of when you do need to take an item away. For those moments, make sure there are amazingly yummy treats around.
This takes a lot of work, it does not happen overnight and you must constantly practice it. Teaching your dog to retrieve is a very helpful exercise for those dogs who pick up everything. Tilley use to be a big picker upper. I was afraid that she would destroy socks, clothing etc so taught her to bring her picked up treasures to us. She was a quick learner and was soon picking up things that people left on the floor for a reward. Your dog may pick up more things but 1. They won't be destroyed by the dog taking it away and chewing on it and 2. They are much less likely to eat the object because you can't retrieve it and eat it at the same time. :)
The new association of the word "drop" is a good one. If your dog likes to retrieve they start spitting out the object faster and faster because they learn that dropping means retrieving again. This action brings that time when you need a quick expulsion closer to a reality.
This is a shortened version of a very long exercise. The more you break a behavior down into tiny steps the easier it is to achieve your final goal and avoid frustration. I will be having a series of e-books coming out in the near future for the long version.
**Of course there are times when it is of the utmost importance to get whatever your dog has in their mouth away from them. These times do arise and yes you must do what you must to get it away for your dogs safety.