Pillowcases for sure. My greatgrandmother's Dresden quilt in a Spacebag ws covered with brown spots. First time in 90 years. It is in a pillow case now.

if you plan to use space bags they should be taken out often- fluffed- refolded with different folds- and checked carfully for any moisture- if you live in a humid area you should never store them in plastic. mildew ruins textiles. and never store one in a garbage bag- you would not believe how many wonderful quilts have been mistakenly thrown out because of a very poor choice- especially when moving- don't put them into trash bags- some helpful help may take them to the dump-just trying to help.

You may also wrap them around the round center rolls that carpet comes on. This eliminates any folds at all. These are usually 12 ft long and can be cut to the length you want, then they can be stored on end in your closet. The quilt can breath, has no folds and is in the dark. The carpet rolls usually are free for the asking.