I once wanted to read on my phone while taking a bath by putting the phone in a ziplock bag. My wife told me I wasn't allowed to do that
Since she gave me the phone for my birthday, I complied.
They make big ziplock bags! I'd probably use one of those.
Steve: there are non-CFC sprays, where you do the spraying manually.
Unfortunately, those are not as clean as they sound. Your finger ends up pretty greasy after all that pumping action. But it doesn't ruin the environment.