Mayco CCKIT-1 Classic Crackles Glaze Kit for Ceramics - Set of 4 Best Selling Colors in 4 Ounce Jars with Free How to Paint Ceramics Booklet Mayco Classic Crackles Glazes add a level of sophistication and dimension to your designs. The cracked effect has traditionally been used to create a vintage or antique appeal. Increase complexity by using in combination with other glazes or design work. Classic Crackles are designed to craze; that is, develop subtle surface cracks in the finished glaze. To highlight the cracks, after firing wipe an acrylic or ink over the ware and wipe off, allowing the ink to fill the cracks. Classic Crackles Glazes are designed to mature at cone 06. Certified Non-Toxic. Not recommended for use on dinnerware. Made in USA. Kiln required.