So my best friends husband died 20 years ago and he left behind a big box of comic books.

From when he was a kid. Many are wrapped in those plastic bags and in very good shape.
Probably 30 or more of them. Some very early Batman and Superman stuff. Loads of them.

How would she go about determining the value of them?
There is an auction house in Dallas that can send somebody out to her place to peruse the
But she is worried about them being undervalued. No hurry to sell anyway.

Any ideas or clues about how to proceed would be appreciated.
We live in the DFW area, if that helps.