The jewelweed (and plantain, if using), have to be steeped in your chosen carrier oil for a minimum of two hours. It is vital not to introduce plant matter directly into the salve because it will cause it to go rancid rather quickly, prevent proper curing, and can cause contaminants to be filtered into the recipe mixture.
Fill the Mason jar one half to three quarters of the way full with the jewelweed and plantain pieces.
Fill up the rest of the space in the Mason jar with the carrier oil. Expect to use roughly three ounces of the oil during the steeping process.
Put a medium to large cook pot on the stove, and fill it just a few inches deep with water - or use a double boiler.
Turn the heat under the pot to low - only.
Place the Mason jar of plant parts into the cook pot.
Steep the jewelweed salve base for approximately two hours over low heat only. If the Mason jar glass becomes too warm to comfortably touch during the steeping process, turn down the heat.
Adding more carrier oil into the Mason jar to ensure the jewelweed and plantain parts remain covered during the steeping process might be necessary.
Strain the salve base mixture through a fine mesh strainer or cheesecloth - discarding the plant parts but keeping the liquid - which should be a shade of greenish orange.