They mention using a playing card between the anvils in the article, and in at least one [1] video they seem to use paper between the anvils as well, so it seem

They mention using a playing card between the anvils in the article, and in at least one [1] video they seem to use paper between the anvils as well, so it seems probable it would work - or at least not hurt. [1] https://youtube.com/watch?v=S8HbhiRlgM0 https://youtube.com/watch?v=S8HbhiRlgM0