THE best way i found, and it may take a while depending on how big you are doing. Trust me it wont be as big as what i did. It was like 4 A3 sheets stuck together it took bloody ages....
Basically place said material over a wait for it...Toaster. Often i switch it on for best effects...
Then just move it around for desired colouring etc. Don\'t let it touch or else it might go on fire etc. The toaster browns it and is really effective. Then for the edges get a lighter and fire to the edge and bat/blow out flames giving a good weathered ripped effect.
Finally for a bit of sparkle, if its big enough and won\'t be crowded by it, you get some red wine and dip the base of a stem wine glass in it then dap the base covered in wine (not sloshing just as though it has spilt and gone down the edge. Press it down a coupla\' times and Robert\'s you father\'s brother. Then you could add some melted wax here and there which is easy and fairly self explanitory.
That\'s all, hope it helps!!
