Mix 2 cups of cold water with gentle liquid hand soap.
Moisten a sponge lightly with the mixture and gently dab away the remaining nail polish.
Dab the area again with a clean sponge lightly moistened with clean water until all of the polish is gone.
Blot up as much of the nail polish as you can with a dry sponge. If the nail polish is already dry, scrape as much of the polish off of the couch with a letter opener or straight edge blade, without scraping the couch.
Dip a small nailbrush or paintbrush into a non-acetone nail polish remover.
Blot the polish or polish stain with the brush. Do this gently and be careful not to get any of the nail polish remover on non-polished or stained areas of the couch.
Continue to blot the polish and stain until it gradually dissolves.
Dab up the dissolved polish with a clean, dry sponge.