After a few years of sealing your floor, you may reach a point where you need to strip all the old sealer away and start fresh.
Every time you seal your floor, even when you clean it before sealing, you'll be trapping tiny impurities between coats. After a while, these impurities will build up and cause the floor to look dull, even when you apply a new coat of sealer. When your floor gets to this point, you'll need to strip all the old sealer away and start fresh. These are the chemicals you need to do it!