Does anyone have suggestions of what to do with old pillowcases?

They are perfect for cleaning ceiling fan blades. Put one over a blade and wipe off the dust. The dust stays inside the case then throw it in the washer.

If pillowcases are cotton or linen embroidered or with tatting, they are collectible and valuable. If they are just plain pillowcases they can be used to store blankets, quilts in, used as laundry bags, cut a hole in middle of end and hang over nice clothes and coats. Used as covers for small decorative pillows. Lots of uses.

Wash carefully and then use to catch popcorn from an airpopper, or use as a jelly bag, or take laundry to the washer, or just about anything you can need a bag for.

All the uses above, and save some for use when someone in the household has just dyed or permed their hair, or has lotion on their face, etc. I also have used them for a cover for an old pillow for kitty to sit on.

Easy to wash, and no loss if she claws them.

King sized pillowcases with a small slit in the stitching of the closed end make wonderful 'hanging bags' for good clothing. I use them for car trips and storage where dust might be a problem. Plastic bags (like dry cleaning bags) do not let clothing 'breathe' but even "ugly" pillowcases can be used to cover hanging clothing--the slits can be very small and usually do not unravel.