When you are making reed diffuser oils, what kind of oils can you mix with the fragrance?

I've seen everything from coconut to olive, anyone have experience with what works best? Thanks!When you are making reed diffuser oils, what kind of oils can you mix with the fragrance?
I tend to like the nut oils like walnut and macadamia, but have also used just plain old cannola oil. You just have to be careful about how large of a container you use because some oils go rancid faster than others and give off a real icky smell when the do. You can never totally get that smell out of the reeds, either, so they are trashed. You can prolong the life of the oil by not placing it in direct sunlight or in areas where there is high heat.