Using poison etc means they will crawl back into their main area and die. You may have to tear a wall out to get to them...
I found this on google search awhile back and had to try it out. I caught one mouse haha... I threw him outside and he probably beat me back into the trailer haha...
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ALot of folks have got the 100% PURE PEPPERMENT OIL from AMAZON and soak up a bunch of cotton balls and keep in a zip-up bag to keep them fresh. Then you can place these cotton balls where you find where they are getting in at... The only big store around here that carries 100% peppermint oil is WEGMANS...
Roy Ken