One thing I've done recently to get the rats & mice that get into the plastic bag rubbish bin locker ( ******* fortnightly collections ) is to get an empty two litre pop bottle retain the cap and cut an inch and a half round hole in it about 3 inches up from the bottom.
( I happened to have a power drill hole cutter that did the job very well once I'd taped the bottle on to some timber , so I could cut the hole in safety with my hands & feet out he way .)
After cutting the hole , washing and drying the bottle to remove all traces of sugar and scents i left it in the airing cupboard for a week to get it bone dry , then put the cap back on
About ten days ago I poured two sachets of the Neosorexin CD in via the 1& 1/2 " hole and carefully laid the bottle on its side so that the hole is facing the right angle of the bin locker floor and back wall then popped a few bricks around it to keep it in place.
As the bottle is transparent it's easy to see that something has a had a feed or two but does not appear to be coming back . come the middle of dec i will empty the bottle into one of this years " Dalek" composter bin to feed any over wintering rodents in there & put new killer in the bottle before putting it back in the bin locker.
The most important thing to remember is that just because you can't see rats & mice it does not mean that there are none. When you actually see them in daylight or early dusk it a sign of a major infestation . So as a consequence you must always use bait stations all year round and expand your cleared perimeter , as well as having the odd inner area bait box in critical places to pick up any that manage to enter the " cordon sanitair " .
Don't neglect the maintenance of all the bait boxes either for that's how the vermin eventually find a way back into the premises once the contents of a box are eaten and the older vermin are dead.
New ones eventually come along from outside of the once cleared area.
Having a small accurate map indicating all the positions of bait stations show a number that is marked on the station in permanent marker is also handy for it's just so easy to forget where all the station feeders are if you have 20 or so around the place. I can also be helpful if you make a number related note of which stations you need to refill for over time you may see a pattern emerging on the map and realise where most of the rats are coming from and put a few more bait stations in that area.