Traditionally, ghosts were believed to appear in shrouds or winding-sheets, as seen in the famous engraving of John Dee raising the dead.
(Which I previously mentioned in 2006, to the delight of the poster who'd started the thread after thinking of that very image.)
In a ghost book I read years ago someone reported seeing what appeared to be the spirit of their late mother, who strangely had a mark or wound on her face.
This observer later discovered that after their mother's death, her face had been accidentally scratched or caught somehow by the people laying her out. Only a couple of people knew about this.
WELL spooky.