The males look rather young, that or their species does not get very big. I used to catch them with claws longer than my middle finger (and I’m 6'3 with not small hands). They always burrowed, but i think your sand may be too moist for them to burrow. If they DO burrow it would be really easy to catch them:
When they see you they will hide in their hole, but only barely inside. Just stick your finger into the sand nearby, hook your finger around underneath them and push up on them and they will be forced to slowly come out. For males just grab the pincher at the joint and you're good to go. For females just grab them anywhere because they cannot pinch hard. (However I don’t think you would get any enjoyment out of holding them other than to just clean the tank, they are, as you know, not slow and do not have a mild temperament like hermit crabs)
I remember washing some of them off to see some really cool designs on their "backs". Looks like yours are coming along too!
Good luck and keep the pictures coming so I can relive my active childhood while stuck in a desk doing IT work.
![Smile :)](./images/smilies/icon_smile.gif)