* Dry out the living quarters first, and then clean out your basement so it is empty of anything that can hold moisture and run it down there as well. Remove cardboard boxes.
* If you have a forced air heating and cooling system with ducts on your home, get the ducts checked. Decades-old houses can have mold, lots of built-up of dirt and other nasty stuff that can cause a foul odor. Your ducts can also be rusting now, so you may need to have them changed.