Corpsing

One of the many skills that a low budget horror propmaker or home haunter should have in their toolbox is the art of corpsing.  The technique of corpsing is a old weathering trick used by special effects artists and prop makers since the early sixties. 

It is essentially covering latex and paint unto a fake skull or a skeleton to give it the appearance of shriveled dried or rotting skin.  If done right it can be very creepy to look at and add a bit of realism to the prop. 

Go here to see some more corpsing technique how-to's.