I have a crocheted afghan that looks to be for a king size bed that I found in my father's house after he passed away. I was told it looked old and I was just wanting to know if there was a way of knowing for sure. Thank you.
This won't be that easy:
Age of Yarn
Step 1
Some yarns lose color with age
Step 2
Some become brittle and break easily
Step 3
Some last for years with no difference
I think it's going to be hard to tell for sure.
Acrylic yarn came out in the early 50's so if it was made before then, chances are it's wool. Sadly, if you wash wool it will felt on you, so you can't test it that way or you will end up with something good for a rug and that's too big of a chance to take.