Same here...I had to take off the brittle stuff (fortunately a small area) inch by inch with a putty knife, utility knives, etc---whatever worked. Then I got down to the nitty-gritty: tar-like black adhesive that had hardened over 50 years to a nearly stony consistency. I was beginning to see why I couldn't find anyone to take on the job! Finally a combination of strong solvents (lots of ventilation) and elbow grease got the hideous stuff off, then I cleaned the underlying concrete. I decided to leave it as it was (I think it was originally a food preparing area) since most of it would be covered by a big plant etagere and the blue, cream and brown encaustic tiles which framed the concrete would show nicely. zemedelec