Old fire damage

[Dan Vleck]

I'm wondering how much to discount a house that has evidence of old fire damage.  The house was built in 1950 and the fire was also in the 1950's according to neighbors.  This is in a nice neighborhood where some of the neighbors have been there since the 1940's, one is third generation.  Anyways, the basement joists are structurally sound, but the burn marks are obvious.  There is no odor or other issue with the house.  How much should a buyer try to discount the house based on non-structural old burn marks.

Thanks for input/experience.