You can use a bottle or glass. Prop it up on the rock close to the hidey hole so that it is at an incline. Put some bait in the bottom of the trap, a piece of shrimp. When the crab enters the glass container it can not get a footing on the slick glass to climb out. Nabbed! Many crabs are nocturnal, so it's best to do at night. Also it's difficult to keep other critters off the bait especially fish. If you have hermits they will also end up in the container. Hopefully, one of the times you will catch a crab. All the best!
Stop slakking and get that crab!
