I used a 3″ chissel and hit the end with a regular hammer, you have to be carefull to keep the flat plane of the chisel level with the floor or you will gouge the floor. And if there is tar paper under it let a damp (not wet) rag soak on it for a while then scrape it off do not use chemicles or strippers because it will turn into goo and will be 100 times harder to get up.
