Hi Jennifer! It’s exciting to hear about your Cottonwood oil infusion. A solar infusion sounds great, I’d just suggest keeping the jar in a paper bag or something to protect the oil from direct sun, while still allowing the heat through to warm it. Stir the jar once a day and keep an eye on it. It may be done between 7 and 10 days, depending on how hot the oil gets. Let us know how it turns out!