Mice Control

November 18, 2012 1:32 PM

The mouse poison we've successfully used for years has run out and is now hard to get as consumers. Is there another brand we can replace it with? Any tips for better sealing our home?

We live in a large, drafty home that tends to get mice problems in the winter if we don't take precautions. Usually, that meant child/dogproof poison traps (we have neither dogs nor children) loaded with Contrac All-Weather Blox, but now they are restricted to fairly large orders because of a problem of consumers using them irresponsibly.

Looking in previous threads, not everyone is a fan of poison traps, but we've found them effective. Without them, we got mouse nests and places where they stockpiled acorns from outside, but with the poison, those issues stopped, and we very rarely found a dead mouse. We also liked that we could simply check the traps every month or two instead of more regularly and still get good results.

Of concern to us is that we'd like poison that is safe for another animal to eat a poisoned mouse (IE a neighbor's dog). My mother claims she read Contrac has an antidote, unlike most other poisons, which is something she'd also like in a poison. Other blocks we've seen online also have a fairly short shelf-life. And Tomcat blocks I bought from the supermarket just don't attract any mice.

When we'd find a hole, we'd fill it up with Great Stuff foaming epoxy, but since the house is large, it's hard to find everything. We've heard good things about steel wool, but we never have any on hand.

I'm open to considering other options if they are effective and useful. I'd really rather not have to deal with kill traps that involve seeing the mouse, or worse yet, no-kill traps that involve moving a live mouse. Are kill traps intended more for diagnosing the mouse problem rather than solving it?

Of note is that the mice stick to the basement, and haven't caused any real damage. We can tell where they've been due to damage. As we're running out of poison, we are starting to see more signs of them.

posted by mccarty.tim to home & garden (14 answers total)

Have you considered a cat? I suspect you have, but thought it was at least worth mentioning.

You might want to check with a local pest control company (perhaps an independent) to see if you can purchase the stuff you've used in the past.

I always use kill traps (plain old mousetraps baited with peanut butter) , if only because I can check them and remove a carcass, avoiding having something die in a wall someplace where I can't get to it.
posted by HuronBob at 2:04 PM on November 18, 2012

Are kill traps intended more for diagnosing the mouse problem rather than solving it?

They're absolutely meant for solving it. My last apartment had a serious mouse problem that I dealt with quickly and thoroughly with kill traps, baited with peanut butter.
posted by Tomorrowful at 2:05 PM on November 18, 2012

One answer, and one solution.

Answer: From the basement, go all the way around your foundation, where it meets the footer of the walls, and inject liquid mortar (the kind you can get in a caulking gun tube) anywhere it even has a chance of fitting. Now go into your attic, and do the same all the way around the eaves (don't seal your eaves vents if you have them, but look for and seal any gaps bigger than a pencil). And the chimney(s). And the plumbing vent(s). And anywhere else you have something going through either the roof or the exterior walls. Now do it all again from outside. And repeat religiously every autumn. You should only get a few mice inside if you do that carefully enough.

Solution: Get a cat. Seriously. You won't win against the mice, ever. A cat, however, will take great pleasure in continually defending your home from small furry invaders.
posted by pla at 2:08 PM on November 18, 2012

As an aside, mice will eat through expanding foam and even wood putty like butter; rats and squirrels will eat through chicken-wire. You need real, actual mortar - Liquid stone.
posted by pla at 2:11 PM on November 18, 2012 [1 favorite]

Steel wool works well in conjunction with the spray foam: push the steel wool in the gap first, then foam it in place.

Also +1 on the cat suggestion. Can you borrow one? We share a long wall with a cat-free neighbor who is always complaining about mice. The only sign I've seen of them is in our backyard, on two occasions over the years, after the mice were captured by our felines.
posted by exogenous at 2:11 PM on November 18, 2012

We used Warfarin pellets that came in little cellophane bags that had a tablespoon or so of pellets per bag. We stuck the little bags behind the fridge, behind bookcases, under the sideboards in the dining room, under dressers in bedrooms. You get the idea. No more mice. We did that every fall and it always worked. Then we got two kittens and we don't need to now. But we did like the results we got with it. (And once the mice ate the warfarin, they didn't make it outside for anyone else to eat them. I suspect that if the house was ever torn down, there'd be lots of mouse bones in the walls.)
posted by ThatCanadianGirl at 3:08 PM on November 18, 2012

Just to be clear, we never found any dead mice in our house, nor did we smell them. I believe the warfarin dehydrates them or something and they end up drying out somehow. In our walls I'm guessing. Anyway, we never had to deal with any unpleasantness.
posted by ThatCanadianGirl at 3:33 PM on November 18, 2012

You can get steel wool in the detergent aisle at the market.
posted by brujita at 4:16 PM on November 18, 2012

Cats and Rat Zappers worked wonders for us.
posted by bongo_x at 5:32 PM on November 18, 2012

Completely sealing up an old house is often next to impossible. I lived in a hundred year old house and with my best efforts could not keep them out. I quite successfully used a combination of kill traps and warfarin. I'd bait the trap with peanut butter and put a warfarin pellet in the pb. The reason being the mice would often get the peanut butter off the trap without tripping it. You need to keep baiting the trap, the mouse will keep coming back, and after ingesting the warfarin they're slowed down so you'll eventually get them. The poison doesn't kill them right away. Put the traps against the wall and lean a board or something over it if possible.

The warfarin does dehydrate them but not so they dry up, ThatCanadianGirl was just lucky they didn't die in some corner and stink. That's why I use the kill trap so I'm sure I can find and dispose of it. May seem cruel to some, but if you get even a minor infestation it's quite disgusting and a significant health hazard.
posted by PaulBGoode at 8:04 PM on November 18, 2012

I'll also +1 on the cat, and while I'm sure you're aware, please don't use warfarin or any other poison if you get a cat.

Contrac is second generation 4-hydroxycoumarin (warfarin), and is really nasty stuff. AKA "super warfarin". The problem with this is that the mouse can eat this and then be consumed (either pre or post mortem) by a dog or cat, and the animal that does the consuming of the mouse is almost certainly going to die. The 'antidote' is vitamin K, but you can't get it in the animal fast enough (vet student-we just saw a case of this). Both the mouse and the animal that eats the mouse hemorrhage to death. It's pretty horrible. I wouldn't use it.
posted by bolognius maximus at 11:43 PM on November 18, 2012

Also, anything remotely edible or nestworthY in the basement - including cardboard and cloth - put that in sealed, hard plastic containers. You want your basement to be the least interesting mouse home ever.
posted by zippy at 12:06 AM on November 19, 2012

Because rodents can bring very serious health issues into a house, I have zero sympathy for mice. We poison them with a desiccant poison like d-CON, and it should kill after just one digestion. You know the d-CON is working because it turns mice poop blue-green. As an aside, we had little luck with physical traps, even following all the best trap placement advice. But the poison worked.

On top of sealing openings with mortar, spray foam and steel wool, check the bottom of all your doors. If there is a gap, the mouse will get in. After the first snow, do a slow walk around your house and you may fine little mouse tracks pointing to their way into the house.

(I understand that steel wool is effective with mice because it disturbs their sensitive whiskers?)
posted by lstanley at 7:33 AM on November 19, 2012

Bolognius Maximus's story is a first for me - I'd always heard that secondary poisonings were more hypothetical but there were few cases. These blood thinning agents are very dosage/size dependent, so a lethal dose for a mouse (possibly more so for a cat sized rat) would be unlikely to be lethal for a dog/cat. However, if and when the dog gets into the cookie jar, so to speak, game over - I know someone who lost a dog this way. This is by far the more likely scenario of unwanted pet poisoning. This is where tamper proof bait stations are important.

(I read this in a blog entry from Bell Labs, who make Contrac and many other poisons. I think they're professionals and would be sensitive to the possibility - and the risks of downplaying it - but sure, they're selling the stuff too.)

Even considering the source, I thought this was insightful:
http://www.doyourownpestcontrol.com/secondarypoison.htm
posted by BleachBypass at 2:19 PM on November 28, 2012