I checked my oil Friday and emptied my oil catch revealing a gritty substance on the bottom that was not sand. It wasnt sand like gritty but it was somewhat a solid that can be smeared with little effort between my fingers, tan to light brown in color. Ive never seen this before and cant find anything on the web about it. Sludge? Using PPPP 5w20 about 3k on oil at the moment. Any suggestions? The paper towl is at work ill try to remember and get a pic tomorrow.