1) Acquire one rat the same color as the mice your mouser eats.
2) Acquire 8ish mice.
3) Place rat and mice together. Allow them to mingle for 5-10 minutes so the mice scent get all over the rat. The more mice the easier this is.
4) Put mouse smelling rat in your mousers enclosure.
5) Make as dark as possible.
Well, that is what finally worked for me. Your results may very.