We did the same thing earlier in the year. I took a putty knife and scrapped off what I could...some would turn powdery and some would smear. I then tackled it with Orange Glo and elbow grease. It looked beautiful when done and conditioned the floor. Be careful because it can make it slick for a couple days. Be careful with paint thinner or adhesive removers because they can strip any protectant that may be on the floor.