I can't remove the grills on my in ceiling speaker grills. I don't know the make/models of the speakers. The speakers were already pre-installed by a prior homeowner before I moved in and there are no markings on the speaker grills. The grills are white, with a total diameter of 11 5/8 inches including the bezel and 9 5/16 inches not including the bezel. I've tried inserting a paint scraper under the edge of the grill and prying with significant pressure but it didn't budge. I could apply more pressure but I don't want to break it. Any help much appreciated.