Best bet would be to pull the side panel off an remove the whole stoker assembly (the firepot and auger) . Not only will this make the unit slightly lighter for easier handling but will allow you to completely inspect and clean the unit prior to putting it back into service. Along those lines you need to remove all items off the unit you can to preclude damage and make it as light as possible. Also if the base is open on the bottom make sure you strap some planks to it, this will prevent damage. Another option is to split the boiler section from the base and remove them as two pieces. This will allow you to reseal the joint and give everything a good cleaning and repaint.
Now that I have assumed (and you know what that gets you!
) to know your business, here is the answer to your question, I'm not sure how the auger comes out of the Van Wert but on the Gentleman Janitors you have to use a slide hammer puller to pull the bushing out of the firepot since it is a press fit. I hope your removal goes smoothly.