Be certain that all of the phosphorus placed in the spoon is oxidized. Be certain that all of the sodium peroxide sample removed has been reacted. In case of contact with concentrated nitric acid, immediately flush eyes or skin with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Call a doctor. Keep the CaO and BaO dry.
Eye protection is always a part of normal laboratory attire.
Wearing goggles is essential for safety during this experiment. Wait one week. Save the barium sulfate for disposal with toxic solid wastes. Heat the deflagrating spoons in a hot flame for 10-15 seconds to burn any remaining phosphorus or sulfur and thereby dispose of them. Sodium peroxide may be destroyed by adding small amounts of the solid to large amounts of water with stirring.