oxyCERTS are soft, non-toxic EVA foam plant inserts that are perfectly shaped and fitted for your oxyCLONE system. With their "no-pinch" design, they hold delicate clones firmly yet gently throughout the entire propagation process. They are fungus- and bacteria-resistant, non-toxic, chemical- and heat- resistant, and writable. They will not absorb water, so there is absolutely no degradation or water-logging. Cleaning is simpleâ€”just use warm, soapy water."