Spraying Cooking Oil/Homemade Cooking Spray Questions

I have a plastic pump-action spray bottle that I bought at Wal-Mart. It worked well for spraying bourbon on a ham (an Alton Brown recipe) and was later used for spraying plain water without giving it any lurking bourbon taste. But can I use it for spraying olive oil and be able to use it for anything else later? Can I really get all of the oil out?

I do want to reduce the amount of added fat in our food as much as possible, but I don’t want to spend money on something whipped up in a lab someplace if I don’t have to. Does plain oil from a pump-action bottle reduce fat or prevent sticking as well as PAM?