For the removable tray, soak in warm soapy water. Scrape the remaining residues with a spatula and scrub with a sponge. Dry well. For impeccable results, there are products available for ceramic glass.
For the fixed trays, clean with a warm soapy sponge. Do not use an abrasive or metallic sponge, as you risk scratching the glass. Gently turn the appliance over to clean the under side of the glass plates. Dry with paper towel.