The process that involves the removal of harmful and waste products from the plants that can be generated during metabolic activities is known as excretion.
The gaseous waste products can include carbon dioxide and oxygen gases released from the openings, like stomata and lenticels.
The solid waste products may include raphides, crystals of calcium carbonate, resins, gums, or rubber that can be stored in several plant parts like leaves and fruits. The plant can release these waste products by shedding their parts.
Therefore, the solid waste products in plants can be rubber, resins, raphides, and gums.