Sheet

; sheet Item Browser: Stable - [ sheet ] Experimental - [ sheet ]
General
Materials	cotton
Volume	5 liters
Weight	1.7 lbs or 771 g
As a Melee Weapon
Bash Dmg	0
Cut Dmg	0
To Hit	-1
Moves per attack	157
Other
Price	1 $

“ A large fabric sheet, could be used as a curtain or bedsheets; or cut up for a bunch of rags. ”

You don't have to break a window to get its curtains; you can use the examine command (e) to tear them down. This will also yield a heavy stick, some string and some nails.