Many foreign particles can find their way into a spark plug well where it's easy for them to get stuck, especially in the unprotected, deep plug wells found on some vehicle makes. When washing your car, water also can find its way around cylinder head threads and into the combustion chamber, oxidizing components if you do not use your car for a few days. Still, you can get water out of a spark plug well using a simple strategy and a few common tools you may already have in your home.