In a spray bottle, mix 1 tablespoon of liquid detergent with 1 cup of water. Shake the contents of the spray bottle to mix.
Spray a small area of the popcorn ceiling with the soapy mixture you prepared in the earlier step. Scrape off the popcorn texture from that area using a putty knife. Store the popcorn texture in a plastic bag. Get the sample of popcorn texture tested from an asbestos-testing laboratory. Asbestos can cause four major diseases; Mesothelioma, Asbestos-related lung cancer, Asbestosis and Pleural thickening. So make sure you proceed to the next step only if the test result is a negative.
Empty the room from which you are going to remove the popcorn ceiling. Completely cover the floor with a drop cloth and hang plastic sheets where the walls meet the floor.
Now you need to start the actual work. Thoroughly damp the popcorn ceiling using water from garden hose and nozzle. This will loosen the popcorn texture. To allow the texture to absorb water completely, leave it for 10 to 15 minutes.
Using a ceiling texture scraper, scrape off all the popcorn texture. A ceiling texture scraper is a specialised tool with a scrapper mounted on a long handle attached with a plastic bag to prevent the popcorn texture from falling on the ground.
Allow the ceiling to dry. Ensure that all the popcorn texture has been removed completely. Chances are that some texture may still be sticking to some areas on the ceiling. Again spray water on such areas and scrape them after 10 to 15 minutes.