you can get a device that plugs into a wall socket & it transmits a sonic pulse back through the wiring of the house which repels spiders & mice etc.
it affects their nervous system & the dont like it & run away- it does not hurt them- its just like how humans cant bear the smell of amonia or a really high pitch noise.
if you google- you will find!
be warned though- in the first 2 weeks of use, it draws all the spiders out that have been hiding in nooks & crannies or under the floor boards & you will see loads. IT WORKS!