Article: Some adhesives, such as "cut-back" adhesives and "mastic," were often mixed with asbestos up until the late 1980s, and are still occasionally used today. These adhesives were most commonly used to bond the floor to tiles or to heating and air ducts, not to carpets, and are often black in color. If you suspect your adhesive contains asbestos, do not use this method, as sanding or scraping the dry adhesive can release dangerous asbestos fibers into the air. Refer to the solvent section instead, or hire a professional to remove the asbestos. Chipping and scraping off the old adhesive can be tedious, although not much more so than using a solvent. The main benefit is a lower risk of discoloring the wood or clogging its pores. After using this method, it should be easy to bond a new stain or finish to the wood. However, if there is an existing finish you plan to leave on, or if you plan to cover the floor with a new carpet, the solvent method may save you some time. Note: renting a wet/dry vacuum from a tool rental service is highly recommended for quick, safe cleanup after the adhesive is removed. If you're lucky, the adhesive will chip right off when you apply pressure with a putty knife. Some areas may take more pressure than others. Only use a plastic putty knife, not metal, to avoid scratching the floor. If the adhesive only comes off in tiny chips, try making it easier to remove with dry ice as described below, or use solvents instead. Pick the widest putty knife you can find to make the task less tedious. If you plan to apply a new stain or finish to the floor, this is your best option for making adhesive removal easier without affecting the wood pores. Place pieces of dry ice in a cookie tray and slide the tray over each section of adhesive before you chip, to make the glue brittle and easier to remove. Always follow these safety precautions before you buy dry ice: Wear thick gloves while handling dry ice, as the extreme cold can instantly cause painful skin damage. Always store and work with dry ice in a well-ventilated room, and leave immediately if you have trouble breathing. Dry ice is solid carbon dioxide, and can fill a small space with unbreathable gas. Do not store in an airtight container, which may explode as the dry ice expands into gas. Clean up the chips of adhesive using a wet/dry vacuum if possible, or a broom. Your local government may require you to dispose of them at a waste collection center, rather than adding it to your ordinary trash, since some adhesives contain toxic materials. However, since you did not use any solvents, you may be able to dispose of adhesives normally; contact local waste collection services to find out about local regulations. The floor may need to be sanded to clear up any scuff marks caused by the carpet installation or the glue removal. Use 16 or 24 grit sandpaper, but go slowly to avoid scraping into the wood. Optionally, sand away the old finish in preparation for adding a new stain and/or finish. Sanding away the adhesive itself is not recommended, as the sandpaper will quickly get clogged and need replacing. Heat from the friction may also melt the adhesive, which can be messy.

What is a summary?
Do not use this method on adhesives containing asbestos. Know the benefits of this method. Use a plastic putty knife to chip off the adhesive. Consider using dry ice. Dispose of the old glue. Sand the floor down (optional).