The author also provides alternatives for other ingredients…
Carrier Oil (Base)
From what I’ve read online, it seems the most common carrier oils to use are safflower oil and sweet almond oil, as they are lighter oils that will travel up the reeds more easily. You’ll use about 1/4 cup of oil for each diffuser, depending on your jar’s size, so try to source inexpensive oil, even if you have to order it online.
You’ll also add a splash of alcohol (about a teaspoon) to the oil mixture to help the oils travel up the reeds more effectively. You want as high a concentration of alcohol as you can get – at least 90%. You can use either perfumer’s alcohol, rubbing alcohol, or vodka. I used 95% rubbing alcohol I picked up from the drug store.
For the full instructions, see NaturesNurtureBlog.com
Image from the same article.