My coworker quit brewing and gave me his old equipment in the mix was 4 gallons of this malt extract..its old,looks smells and tastes like molasses, has kind of a sharp after taste...should i brew it or dump it?
I'd probably brew it just to see. That being said I already have a pretty solid pipeline so I wouldn't be wasting any space in doing so. If I had no brew to drink I'd probably brew a batch with fresh ingredients first then give that one a shot.
You could always use it as a yeast starter.
When I make a starter I let it fully ferment, and after 5 days put it in the refrigerator and chill it, then decant off 80% of the spent beer, and only pour in the sludge into my wort.