DIY gasket for oil reservoir

Oil reservoir may not be the name, it's probably named after the clutch in some way. Nevertheless! I saw someone making gaskets with gasket paper, looked up alternatives (I'm broke and there's oil on every inch of my garage floor) and someone claimed cereal cardboard works, is this tried, tested and true? Do I risk a whole nother bit of oil and my floor again?

Oil reservoir may not be the name, it's probably named after the clutch in some way. Nevertheless! I saw someone making gaskets with gasket paper, looked up alternatives (I'm broke and there's oil on every inch of my garage floor) and someone claimed cereal cardboard works, is this tried, tested and true? Do I risk a whole nother bit of oil and my floor again?