Plaster coving, usually found in older homes, is very delicate. Your plaster may have been in its current spot for hundreds of years. In many cases, the plaster coving has been covered and re-covered in multiple coats of paint. Removing paint from any plaster surface should be done with great care. You may be working with very old or antique surfaces, which are often very valuable. Have your plaster evaluated by a professional before proceeding with any restoration.
Wipe the plaster coving with a clean, soft rag to remove all dust and debris.
Scrape away as much paint as possible with a paint scraper. Apply pressure gently to the paint, working the tip of your paint scraper under the paint without breaking through the plaster. Press lightly away from you to remove paint. Remove as much paint as possible with this method.
Put on gloves and a mask. Open and stir the paint stripper thoroughly. Choose a methylene chloride-based remover. This type of stripper will remove paint without damaging the plaster.
Test the chemical stripper on a small patch of the plaster to make sure the stripper won't damage the plaster. Choose an inconspicuous portion of the coving. Apply a 4-inch-by-4-inch coating of remover. Allow the chemical to penetrate the paint for 30 minutes. Scrape away the paint using various sizes of paint scrapers. Choose a small scraper for detailed scrolling and a larger scraper for the flat portions of the coving. Make sure that the plaster is undamaged.
Continue to remove paint by applying chemical paint remover to the rest of the coving, working in 4-foot sections at a time. Allow the remover to penetrate the paint for 20 to 30 minutes. Scrape away the rest of the paint.
Dip a clean rag in white spirit. Wipe away the chemicals on the coving with white spirit. Wipe away the white spirit.
While scraping you may knock small portions of the plaster loose. Set these pieces aside for replacement. Use construction adhesive or putty to reattach the loose pieces once you have completed your refinishing.
The Consumer Product Safety Commission recommends that you use caution while working with chemical paint strippers. Create as much ventilation in the room as possible with open windows and fans. Always wear gloves and a mask while working with noxious chemicals.