You may want to try convincing the mice to move out. You don't want to poison them, because then you'll have dead mice in your walls... But you can't negotiate with mice...
Rodents do not like the smell of camphor. Camphor is the turpentine-like resin of a tropical tree, although much of it is made synthetically now. It is what you smell in Vick's Vapo-Rub. You can usually get campor in a pharmacy - if you can't find it, get Vick's Vapo-Rub. You may want a couple of units.
The next challenge is that you need to get the camphor inside the walls. Don't use a hammer! If you are comfortable with electrical outlets, you can remove the cover of an outlet, loosen the outlet box, and slip the block of camphor into the wall. Make sure the camphor has been unwrapped before you put it in place. If you use vicks, take off the cap of the jar and use a nail to punch some holes in the cap, then put the cap back on the jar. You may want to tie a string to either the block or the jar so that you can get them out of the wall should you find you need to. Then close things up.
You might smell the camphor a little (probably not), but you'll get used to it, and the rodents will like it a lot less than you do. Bats are not rodents, but they may find the odor unpleasant enough to leave also.
The spiders can be chased out with a product called Buhach - it is powdered pyrethrum daisies.
Do this in the basement - you put a heaping tablespoon into a non flammable (ceramic or metal) container and light it with a match. It will smoke like powdered incense, but it smells like a cigar - a cheap cigar. The smoke contains some of the pyrethrin, and because it is smoke, it goes everywhere. The spiders will find this offensive and leave.
http://www.buhach.com/
- Nathan Natas, offender of man and beast
