OK..Im going to respond to this post NOT because Im trying solicit business, but because I am married to an exterminator and have to listen to stories like this often... If you have a mouse problem, you really need some professional help.. While store bought stuff (like the d-con and the mouse traps) seem like they help, they really dont.. What you're doing with those is basically baiting the mice.. in other words, drawing them to you. This isn't a gaurantee that theyre going to die. It IS, however, a gaurantee that at least one or two of them are going to get fat and breed. You may catch one or two, but two or three are going to be smart enough to stay away from the traps and poison.
As for the steel wool and foam insulation, BAD idea.. For many reasons, just a few of which Ill name. First of all, the mice will just chew through this stuff.. Might take a day, might take a week, might take a month, but I promise they'll be back. And then you'll have more than a mess, youll have an ugly mess. On top of that, if youre sealing these things in your walls, well, you can guess what will happen when one or two of them die.. Then its a smell youre stuck with for quite a while, while still having the live ones to deal with as well.. Two words: bigger problem.
There really are some cheap AND humane ways to deal with your mouse problem through an exterminator. Not only that, but if you call an exterminator, youre going to save money on continually buying products from the store that essentially dont work anyway. Poison isnt the only route you have to take (although it is the best, AND perfectly safe for kids and household pets, as it drys within an hour and is D. very discreetly.
If you Do decide to call an exterminator, DO NOT HIRE them unless they gaurantee their work. There are a lot of companies out there who buy cheap/outdated product and then water it down, thus making customers keep paying every ti me they have to come back to deal with a problem. Over the years, there have been a lot of people who have left my husbands company to pay cheaper prices (which add up to be more expensive than him anyway) who have had their problems just compound and get worse, then theyve come back to my husbands company and cant believe how fast their problems are taken care of. Definantly shop around before you hire anyone!
-Hoping your mice are long gone...
Oh yeah, and your exterminator doesnt have to spray inside the house at all, he/she can just treat the exterior to prevent them from coming in at all.. Only problem with this is if theyre already in.. You might want to have both the inside and outside D. the first time around, that way it takes care of the problem at hand AND prevents the problem in the future.