Spruce up vases with some simple lines or dots. The results don't have to look perfect; it's more fun if it's a little unique. "Imperfect is Perfect" is the current mantra! Paint/draw with porcelain pens. Clean the vase thoroughly before you begin. Draw patterns. Let dry for 4 hours, then harden in the oven at 160°C for 90 minutes. After hardening, the vase is dishwasher-safe (if the vase cannot be washed in the dishwasher, you can simply leave the design as is without hardening it in the oven). Remember that crystal vases cannot be hardened in the oven; they can crack.