Don't waste your play time scraping primer off your glass piece! Announcing a breakthrough in kiln wash and shelf priming. Hotline Primo Primer fires to 1550°F (843°C) and higher. Glass does not stick to the shelf. Primer does not stick to the glass. It removes from shelf after firing by brushing or by wiping with a damp sponge. No more tedious and messy scraping. We love this product!