First we started with food. Stuffing chicken in the toe of the shoe, rubbing baby food on the inside. That didn't work - too licky. We don't want shoe licking we want shoe chewing.
We ended up drilling holes into the shoe and zip tied a rawhide chew to the inside of the chew. That seemed to work quite well. One of the dogs Buck liked it immediately. The other dog Molly, got bored with it quickly if she couldn't get the chew out - she we had to place chips of chicken jerky behind the chew that she could get to and "win", this made her happy and kept her going back and looking for more!
Operation chew shoe was successful!