Sandflea Preservation

I have heard that you can freeze sandfleas for a long period of time and still use them for bait. The only frozen ones I have used were store bought and most crumbled when trying to put them on a hook and the others came off when being cast into the surf. I would like to store some up this fall to use in the early spring. I have read where some people blanch them for a few seconds and freeze them loose in plastic bags. Others say let them die, rinse and freeze loose in plastic bags. One guy salted them before freezing to toughen them and someone else froze them in saltwater. What is the best way to keep them useable?