I preserve my 'flimsy' paper patterns by ironing them onto lightweight interfacing. Works wonderfully and folds neatly to place back into the envelope. You can see all the markings thru the interfacing. You can usually buy about 3 yds in a package at the fabric store for $1. At least that's what I pd last time (might have been on sale)...then trace the size you want to save before cutting away.