Help with mice anyone?

[helenhabbit]

Okay so I think I have mice behind my boiler
I have already caught two in traps
and put poison down everywhere
when the boiler comes on I can hear them but when its not I cant
and its not just the pipes creeking because pipes dont scratch
anyway
is there like any smells or anything mice do not like
I've heared peppermint?
any other ideas?

Thanks
xxxx