Best floor cleaner for stained hardwood?

Drop of ammonia in distilled water with a microfiber cloth

I've got heart pine floors that are probably close to 100 years old now and I had them refinished about 20 years ago and I just use a damp mop to get the dust up once I sweep the floors.

I have one of those commercial mop buckets and will squeeze the mop about 3-4 times before it hits the floor. It is just barely damp and it hasn't had any negative effect on my floors.

I add pine sol and Odoban in equal parts to my hot mop water to clean my floors.