What is done in the lab with living specimens after they die? What are the effects on Charlie?

The specimens are frozen, and then they are disposed of in the incinerator. Charlie was upset and asked to take care of Algernon's remains himself.

"Not Algernon," I said. "Look... if and... when... I mean I don't want him dumped in there. Give him to me. I'll take care of him myself." He didn't laugh. He just nodded. Nemur had told him that from now on I could have anything I wanted.