Many companies cold-extract lemon oil from lemon peels and market it as essential oil. Manufacturers package lemon oil either as pure essential oil or mixed with other oils or water for use in cooking, skin care and household cleaning.
Lemon oil is useful in skin care because it acts as a natural astringent, tightening pores and removing dead skin cells. It's also a natural antiseptic. People make lemon oil at home by mixing one part lemon zest with one part olive oil in a small bottle and leaving the mixture on a windowsill for a few days, shaking the bottle a few times a day.