Plaster was common as a type of decoration during the late 1800s and early part of the 20th century. It was used in finials, medallions and other decorations used on the walls and ceilings of homes. If you own an older home, then the odds are good that you might have plaster decoration. You can remove paint from plaster with a simple product.
Find a product called Peel Away, which is available from most hardware stores and home improvement stores. If you can't find Peel Away, use KS3 or another poultice product. These remove paint quickly, without causing the paint to flake off.
Protect the surrounding areas by covering with plastic tarps and tape. The Peel Away quickly strips the paint, but can also cause discolouration in carpets and strip paint from your walls. Make sure to cover any area that you want to protect.
Apply a thick coat of Peel Away to all the plaster surfaces you want to treat, at least 1/4 inch thick. Place the special paper that comes with the product on top of the Peel Away and leave it sit for at least 12 hours to give it time to affect the paint.
Remove one edge of the paper and check the plaster underneath. If it looks clean, then you can remove the rest of the paper. However if the plaster still has paint, let it sit for another one to four hours, checking it every hour.
Remove any traces of paint left behind with soapy water and a stiff-bristled brush. Coat the plaster with water and gently scrape off the paint with your brush. If any traces of the paint remain after you've done this, let the surface dry and then rub the area with a fine grade sandpaper. The plaster is now ready for a new coat of paint, or a sealer to protect it from water damage.
If you're only trying to remove paint from plaster because you're worried about lead-based paint, you don't have to worry. You can use a speciality sealing paint that goes on clear and coats the lead paint.
If you think there's lead paint on your walls or plaster, then use a face mask and gloves when stripping off the paint. These items protect your skin and lungs from the lead paint.