We used tung oil. I was pleased with it because it didn't smell too overwhelming, nor did it change the color of the wood. Apparently there are a lot of different products to protect your wood, and perhaps the reason I felt the project so overwhelming was simply because at first I wasn't sure we picked the right one. Not to mention Steve was convinced we'd need five coats to keep our wood from turning yellow over time, and between each coat the whole house would need a good bristly scrub. Well it got a scrub, I missed the whole thing, but the house only got two coats of varnish, and somewhere along the line me and Steve decided two was good. Call us lazy, I don't care.