How can I clean old wood floors that are not sealed.

The best news is you don't have to strip the floor. Start in the corners with a barely damp scrubbing sponge with a degreaser cleaner like PineSol. I'd dirt and wax are built up along the edges of the wall, you need to scrub those, too. If the rest of the floor is in bad shape, you need to scrub the whole floor by hand, also. Once you have the dirt and wax scrubbed up, you need to mop the floor with a barely damp mop, using separate water to rinse the mop frequently. Rinse next to make sure all the residue is gone. Then you need to seal the floor yourself. Cleaning will be so much easier the next time. Best wishes 😇💞

Scrub them

http://homeguides.sfgate.com/safely-cleaning-unsealed-wood-floor-31115.html

Use Murphy's oil soap, with a damp mop, follow the directions on the bottle.

murphys oil soap is really amazing for this!