I've done two things. When it first started to happen I was a lot more worried about it. You can take a Q-tip and use the middle part to open the mouth and then remove the foreign object. Most of the time this takes more than one pair of hands. I now just leave them be and eventually they will fix it themselves. As you can imagine this is what they would have to do in nature.
This is just my experience with it. Unless they are unable to close their jaw/mouth I would recommended just leaving it.
Okay, thank you. He seemed to clear it up himself. I was just concerned because I have absolutely no clue how susceptible snakes are to impaction.