I switched to those plastic slow cooker liners last month and had one split right down the side while cooking a pot roast. The meal was ruined and the melted plastic smell filled the kitchen, plus I still had to scrub the ceramic insert for 20 minutes. I know they are convenient, but one bad batch in a hot cooker can wreck dinner fast. Does anyone else double up the liners or do you just stick with greasing the pot and using parchment paper? I am trying to figure out a safer option before I host Thanksgiving for 8 people next week.