Are your scissors or kitchen knives no longer as sharp as they once were? You can quickly sharpen them again without a whetstone.

 

Cut lengthwise through a piece of fine sandpaper with the scissors that are no longer quite so sharp. The friction on the grains sharpens the scissors as they cut through.

You can sharpen dull knives by folding the fine sandpaper once and placing the knife between the folds. Now cut the sandpaper lengthwise along the kink to sharpen the blade again.