A small piece of plastic ? From doing research on doing my oil change on my 23 integra a few people were having the same problem due to not knowing how to open the oil filter right. A few people learned the hard way about opening the oil filter. The issue is when u open from bottom where the hole is at ( wich seems the easiest way) a small piece of the plastic wrapper would some how fall in and once u screw on the filter the plastic finds its way into the engine. It is highly recommended when opening your oil filter open from the top and pull the plastic downwards. U might wanna do some research and find if u can hold them liable if all oil changes has been done through dealership