RSO is concentrated cannabis oil (CCO) and requires a solvent like ethanol alcohol. I find ethanol rediculously difficult to procure and too expensive for my taste, and I’ve learned that an olive oil or coconut oil extraction makes medicine every bit as effective therapeutically, without the dangers of fire and explosion many other techniques can have.
I find my base recipe of 1 gram of bud to an ounce of carrier oil with a tablespoon of liquid sunflower lecithin for every cup of that carrier oil to be effective for just about everything. For serious meds my recipe is 100 grams of dried bud to 500 ml of carrier oil is my go-to.
Here’s a link to the Instant Pot picture tutorial. That might be helpful.
Olive oil is the preferred choice for everything except liver disease or if you’re making oils for recreational purposes. In both of those cases coconut oil is what you’ll be wanting.
Grape seed oil absorbs into the skin better and that’s what most choose for a topical.