Advice on how I can make my own 1 cal cooking spray like frylight I've been using frylight for years, but I'm trying to swap to a healthier version with no chemicals. 

I've been doing some research on the internet and some people have talked about making their own version by getting a spray bottle and mixing 1 part olive oil to 7 parts water. Then just shaking the bottle well before each use. However I'm concerned that the lack of preservatives could mean that the water will go stale and will be dangerous to drink. 

Has anyone done this or can you offer any advice for the best way to do it? 

Thanks in advance!
Why not just pick whatever oil you want to use, put some on a paper towel and wipe the pan with it? It'll have the same affect or just skip the oil all together and get a really good non-stick pan? 

The only way to get oil and water to mix is to use an emulsifier.