The snaps that hold your dodger to the deck can become a nightmare to work. Being exposed to a marine environment for a short amount of time can cause the metal components of the snaps to corrode. This corrosion can make any attempts at manipulation a true chore. If the corrosion gets severe enough, you do run the risk of ripping the snap out of the canvas!
To avoid these problems, oiling the snaps will help keep corrosion at bay. I would caution against spraying oil onto these snaps, as it will get on the canvas. If you have light colored canvas, these oil stains will show up clearly from a distance!
Instead of ruining your canvas to maintain your snaps in operational condition, use a Q-Tip. Wetting the cotton end of the Q-Tip with oil will safely contain all the oil you could need for the snap without having excess run into the cloth around it.
Simply place the oil soaked cotton into the snap in the canvas to lubricate the mechanism. This will lubricate the metal and help retard any corrosion without putting too much oil into it and causing it to run into the canvas.
Now your snaps will remain easy to operate and provide you years of headache free operation.