Water and a stiff brush is all you need
Yes, actually — for campfire cast iron, forget the soap unless it’s absolutely caked.
Here’s the thing: a campfire gets hot enough to burn off anything. You don’t need to scrub like you’re prepping for surgery. Let the skillet cool just enough so you don’t warp it (splash water on it while it’s screaming hot and you’ll crack the iron), then scrape out the big chunks with a metal spatula or a wooden scraper.
Pour in a little water — maybe a quarter cup — and let it simmer over the dying coals to loosen the stuck bits. Then scrub with a stiff brush or chainmail. No soap needed unless you’ve got something greasy or rancid that water won’t tackle. Even then, a dab of camp soap is fine; modern dish soap won’t ruin a good seasoning.
Rinse, wipe dry with a rag or paper towel, then put it back over the fire to evaporate every drop of moisture. Once it’s bone dry, rub a thin layer of oil over the whole surface — inside and out — while it’s still warm. That’s it. Don’t drench it; you just want a sheen.
Future you will thank you for not putting a wet skillet in a bag.
