I did a lot of things with them, but a bunch of them ended up at Hopkins Marine Station where they were milked for venom. I hand collected them, but I knew what to look for to keep from being envenomated, and I put them in plastic jars rather than mesh bags (which is risky). You also don't want to put your hand into a container to try to retrieve one, the deadly species become agitated after they've been in a collecting bag or jar for an hour or two, and will fire their harpoons in defense.