so i changed my oil yesterday. i am using the last of my BOGO synpower (will be switching to PP) i ran 7500 miles on this oil run.. a question that i have been pondering is what exactly is trapped in an oil filter? i allowed most if not all the oil drain out of the purolator (regular one) and compared to my new regular purolator and that sucker was much heavier.. i mean what can be trapped other than very small particles?? is it just the filter media soaked in oil causing it to be that much heavier? just something i have always wondered..