I used baking soda and hydrogen peroxide for toothpaste growing up. While making hydrogen peroxide isn’t easy on an individual level, it is readily available.
So there you have it. You’ve solved the whole self-sufficiency dilemma.
Speaking of Maine, it’s a good place to learn about self-sufficiency. The real trick is to grow enough weed in a short season to have enough to keep you through the winter, and not get caught or have it stolen. The latter risk is greater than the former, by the way.