How do you safely remove the old black adhesive used for flooring?

I had this problem when I pulled up the particle board underlayment that covered the original oak floors in my kitchen. There was old linoleum under the half inch underlayment so a green flesh was also glued to the adhesive. I needed an inexpensive and relatively non-toxic method due to kids and pets in the house. I poured small mounts of boiling water on the adhesive to soften it and then scraped with a 5-in1 tool. This worked very well but takes a lot of elbow grease. On the tougher spots, I poured small amounts of undiluted ammonia to dissolve the adhesive. Make sure there is ample ventilation and keep children and pets away.

Heat gun works good, or a high powered blow dryer and a putty knife. . I removed a bathroom floor with this method.

I removed old linoleum from both my kitchen and bathroom (2 layers in the bathroom). The biggest problem you may have is whether it has asbestos in it. If it does - DO NOT use a sander. Water minimizes asbestos particles. I used three main methods - each one followed up with an old fashioned scraper, on my hands and knees, gloves, and a mask. One - old, hot soaked towels which allowed the glue to soften (left them on for at least 20 minutes). Two - continuous mopping with hot, hot water and a little bit of Dawn dish soap. Three - steam mop with angled nozzle.

There are paint strippers that would work . Goo be gone would be great but that would be expensive if it is a large room. Stripper would be my choice