If you're going to do it with coffee there are a few options...

Option 1 (The Weak Coffee Stain in a pot on the stove)
1tbspn into 500ml of water on a stove, boil and skim out the coffee grounds then do what CoyoteMax did.

Option 2 (The REALLY Long Black)
Make percolator coffee with double the water or half the coffee of usual then do what CoyoteMax did

Option 3 (The Grinds Rubbing)
Get a dishcloth, put a big spoon of coffee grinds into it, tie it into a ball and put it into boiling water for a little while (until you see the coffee soaking back out into the water). Wrap a dry dishcloth around it and rub it onto the paper. This is really good for adding in those "random damage" marks.


Done these on all sorts of things before... so give them a whirl. Variations on the tea theme but they work nicely.