How do you get dirt from between panels on light hickory floors?
Here's a post that might help - https://www.hunker.com/13421552/how-to-clean-wood-floors-with-black-streaks-between-the-wood-joints
Hands and knee,s and a soft scrub brush.
Vacuum it first, to get any of the loose dirt, then use a toothbrush to get into the cracks to loosen the dirt, try vacuuming it again to see if that takes care of getting it all before you resort to cleaners.
After you've cleaned out the dirt, I would fill the floor so you don't have to do this all the time. They sell the filler in pails at the home stores in various colors.