Stinky basement?

My summer project is to clean out my parents' basement... it is definitely cooler and more humid down there, and has little air flow... so after so many years... it has that very yucky stale-basement smell. It also needs to have walls fixed and overall needs to be refinished. It is more of a cellar, than a basement... if that helps the description.

Aside from getting a dehumidifier (right now it is so cramped... no room... I'm working on) what things could I do in the meantime? I was thinking at the very least, light some scented candles... if only for the smell.

But, I am open to any suggestions :)

Thanks :)