Acetate velvet works best. Stamps with a large surface area, without fine details work best. Foam stamps work well, but eventually deteriorate from the heat. Use an iron press or an iron without steam holes, such as a travel iron. Heat the iron to the highest setting the fabric can stand. Spray on a little water or spray starch first (don't soak). Lay a piece of cardboard on the ironing board, then the stamp (design side up), then the velvet (pile side down), then a press cloth. Press for about 10 seconds.