quick cold water extraction is the only predictable method. any other recipe (naptha wash, everclear, or whatever) are not going to work unless you have top-notch lab skillz, equipment, and solvents.
peppermint oil does NOT contain any appreciable acetaldehyde unless it is freshly distilled from fresh plants.
menthol on the other hand is definitely present in peppermint tea, oil, and gum. menthol is a very good natural calmative and anti-nausea agent. experiment with ginger/lemon/honey tea as well to see what your own body reacts best to.