Here are some photos showing the stages of cutting down an antique composition ornamented gilded frame. The long dimension is the correct size, so only the shorter sides needed to be cut down, approximately 1 3/4" needed to be removed. First the two cuts were made at the required size. This left three sides joined together at the correct size and the fourth side still had the excess moulding held in place by the original mitres. A screwdriver was used to carefully push the mitre open, with a bit of prying apart the corner joints were separated, the nails (x4 in each corner) were then removed. The mitre was tidied up with some sanding and scraping, and the last photo shows the frame ready to be joined together (the bottom length is not fixed yet in this photo). There is a small amount of filling required where the nails were, but apart from this the corners came apart very well.
