HCA: Hermit Crab Association

A few of mine have molted recently and a couple have left a ditch making the spot they vacated obvious. I looked in the ditches and found the exo from a big pincer and a couple tiny exo leg pieces. Can I save these for a future molter with a stolen exo or some other crab mishap? And if so, would I simply freeze them in a freezer bag?

I usually just save any extra bits in a baggie. I've never froze them or done anything special to it, just kept it in a drawer or on a shelf for future usage.