If you have ever seen spontainous combustion, you will be a believer of "don't pile oily rags". Many moons ago as a teenager it happened in my basement. I couldn't believe my eyes, first smoke, then flame. truely amasing. just another thing you learn when growing up. never stop learning, it keeps you young.
There are a number of excellent products for things like vinyl shutter restoration that work well to a point if the color itself has not faded drastically. Try some off the products from the auto store too.