Doodling makes me happy and I used to throw away all the drawing when I am done with it.  Those that I saved were on photocopy papers (A4). I like to use a softer B pencil and it is the darker one that I most prefered.  It gets very messy if I work for a long time on a drawing.  I will see that my wrist, palm or forearm have done a great job of smudging up entire drawing.  Usually I would use a piece of paper under my hand to prevent making contact with the drawing.  When done, I would spray coated all the finished drawings.  It is a thin like lamination to preserve the drawing.  – *emulated manga drawings were done years ago.