Hello, my name is***** and I have over 20 years of experience as a veterinarian. I am sorry to hear that Moxie ingested some Paperclay with joint compound added some time within the past 4 hours.
The good news is that neither one of these products is toxic.
Paper clay will quickly break down when exposed to liquids, so I suspect Moxie's stomach acid has quickly broken that down.
Joint compound usually has polymers added to make it more flexible so as to decrease cracking, that will make it unlikely to break down completely, but I wouldn't expect large clumps to linger.
If she had eaten a large quantity then I would be concerned that it may settle, irritate the stomach and intestine lining much like sand would and possibly lead to an obstruction if a lot of joint compound only with high levels of polymers were in it.
But because it was a small amount and had less joint compound than Paper Clay she is not likely to have serious effects.
You may see some cramping and nausea, she may have harder than usual stools and some difficulty passing them, but that should be it.
To ease stomach upset and help push the grit through start a bland diet of 1/3 boiled, lean hamburger (or boiled, white skinless chicken), all fats and juices drained off the meat, mixed with 2/3 boiled, plain white rice. Add warmed low salt chicken or beef broth to get additional fluids into her. Add 1-2 tablespoons of canned pumpkin (not pie filling, just plain pumpkin) to each meal to soften stools and ease irritation while helping push the grit through. Feed several small meals a day.
Feed this for 3-4 days, and if she does well then transition her back slowly to her regular diet.
Please let me know if you have any further questions.