I have a small cabin with cedar lap siding. The siding was put on a couple years ago and has never been treated. The cabin is in the woods; I love the dark grey look of weathered wood--the cedar is graying nicely but I want to make sure it's protected. The people around here tell me to treat it with motor oil. Several of them have used a mixture of used motor oil and--transmission fluid?--on their homes. It certainly seems to last and protect the wood. I couldn't find much online about treating cedar siding with motor oil. A few vague references to used oil being a carcinogen, and lots of talk about preserving the original color of the wood. Since I'm not interested in preserving the original color and like it naturally weathered, would motor oil be a good option? If used motor oil is bad, what about unused? Any suggestions from people with experience?