A basic explanation of duplicate stitching, also called Swiss darning, done as surface embellishment. A knitted foundation piece is shown here, but this could be adapted to crochet as well (particularly a slip stitch piece, which mimics knitting).
For Dining Room-Mercury glass mason jars. Looking glass spray paint, equal parts vinegar/water spray bottle. Spray with water mix then add light coat of spray paint. Allow to dry. Use a paper towel to wipe away bubbled areas for completed look.