They are most likely only valuable to a very select few of collectors or perhaps a textile museum. But to people like us, it's very valuable. To you they are very valuable for sentimental reasons.
I have an antique quilt made by my great-grandmother about 100 years ago. I took it from my mother as she would have totally ruined it by letting pets sleep on it or just lost it. I would love to have it preserved it some way and then hang it on a wall in my bedroom.
If you do find someone who wants to buy one, I recommend keeping one and perhaps having it framed or encased in glass as a momento of your mother.
Knitting to keep my sanity. It's working... kinda...
OTN: Dr Watson's Cable Crew Neck
OTN: Writer's Cardigan