Fill a glass jar half-way with chopped, fresh jewelweed, that's been allowed to wilt for a few hours.
Pour the oil into the jar, adding more if necessary to completely cover the plant matter.
Set the jar down into a small saucepan containing several inches of water.
Heat the pan over medium low heat for 2 to 3 hours, indirectly heating the oil and speeding up the infusing process.
Remove from heat and strain through a fine mesh sieve into a new heatproof jar.
Return the jar of infused oil to the small saucepan, adding more water to the pan if needed.
Heat the pan (still filled with a few inches of water in the bottom and containing the jar of strained oil), over medium-low heat for an additional hour to help evaporate out excess water content.