Another option requires a heat lamp and really cheap paper. You crumple, fold, spindle, and so on. Apply the heat lamp and the paper will rapidly brown and become fragile. If you leave it folded (ideally with several other pages) then the edges will brown faster than the inside. Roasting it for a good long time will make the edges crumbly. Try not to let it catch fire too much.

I am told that making the paper more acid with something like vinegar between the scuffing and roasting will make the browning go faster. The more acid the paper the faster it goes.

The best paper I ever found for this was cheap white quad-rule graph paper. I drew a quick dungeon map on it. The blue lines washed out with a quick dip in water and the paper was acid enough that it browned rapidly. I applied a little extra heat to one corner of the folded map and the result was nicely asymmetric and crumbly when I opened it up again.