Have you ever found you needed a slip proof surface on something small like a ladder or skateboard or anything you have that needs a safe footing.
Take my sons bed ladder for example. Not only was I worried about him slipping on the metal rungs but a little padding made it more comfy for the climb.
I just went and found a fairly thin door mat and measured the size I needed for each rung, cut them out and used rubber cement to place them. Now its slip proof and cushioned a bit.
I had first thought of sandpaper or something like it but that would be uncomfortable I think, maybe an idea for a skate board though.
Hope this little hint is helpful!