Using a box trap for muskrats is very effective with the right technique. With a little preparation and proper placement you will have no issues bagging muskrats with a cage trap.
Set your box trap directly on top of a floating log. If there are no floating logs in your location set your trap on a board to float it. The placement must be near where the muskrats feed and the box trap must be attached securely to the log or board. It should have no wiggle to it at all once placed.
If the log might drift it also must be anchored so it will stay in place near the feeding location.
Now take some carrot and chop them up into one inch sections. Place a trail of the carrot pieces from the front of the trap all the way to the back end.
You can also add some muskrat gland bait to the back end of the box trap.
The last thing to do is to soak enough leaves and grass to cover the entire trap. Spread the wet leaves and grass over the entire outside of the trap, without blocking the opening. This will give the appearance of a small muskrat hut.
This setup is great at luring in the curious muskrat and has never let me down.
For more muskrat tips check out these articles