You go up with a flashlight, and there they are. Little black grains scattered across the insulation like somebody spilled coffee grounds.

Mouse droppings. And now a simple attic cleanout in Boise feels like something you shouldn't be poking at in a t-shirt and gym shorts.

We get this call more than you'd think. Usually October or November, when somebody finally climbs up to grab the Christmas tree.

Here's the short version: it's fixable, and it's nowhere near as dramatic as the internet makes it sound. It does change the job, though. And it changes what it costs.

Why mice end up in Boise attics

Mice don't need much. A pencil-width gap at the soffit, a loose screen on a gable vent, a hole where the cable guy drilled through and never sealed it back.

Older homes on the Bench and in the North End have the most ways in. Seventy years of settling will do that. But we've pulled nesting material out of five-year-old attics in Meridian and Nampa too, so newer isn't the same as sealed.

A few things that tell you something's living up there:

Droppings clustered along the tops of joists and in corners, never spread evenly
Insulation tunneled through or shoved into piles
Shredded cardboard, paper, or fiberglass wadded into a nest
A sharp ammonia smell in the closet or hallway below
Scratching overhead right after dark

Two or more of those and you don't have a mouse. You have mice.

What droppings change about an attic cleanout

The boxes and the old furniture still come out the same way. What changes is how everything gets handled, and what's worth keeping.

Dry droppings are the real issue. Sweep or vacuum them and you throw all that dust into the air, which is exactly the part you don't want in your lungs.

Deer mice out west can carry hantavirus. Idaho has only ever seen a handful of cases, and the reason it stays that rare is that people handle this stuff correctly. Salmonella is far more common and a lot less dramatic.

Urine is the sneakier problem. It soaks into fiberglass batts and blown-in cellulose, and it doesn't just dry out and disappear. That smell drifting into your upstairs hallway? That's where it's coming from.

Heads up: Don't sweep it, and keep the shop vac out of it. Mist the droppings with a bleach solution, about one part bleach to nine parts water, then give it five minutes before you wipe it up with paper towels. Wet handling keeps the dust down, and that's the whole ballgame.

Contaminated insulation almost always comes out. You can't wash it. We went through how that part works, and what it runs, in our post on whether the old insulation comes out during an attic cleanout.

Cardboard boxes that got chewed through? Those go. Sealed plastic totes usually wipe down fine.

Fabric is the thing people argue with us about. Old mattresses, upholstered chairs, boxes of clothes stored up there. Don't fight for any of it, because cleaning it right costs more than replacing it.

How to clean it up without making it worse

Doing this yourself? Get all of this together before you climb up:

✓An N95 respirator, not a cloth mask or a bandana

✓Nitrile or rubber gloves you can throw away after

✓A spray bottle with the bleach and water mix

✓Contractor bags, doubled up

✓Long sleeves and pants you won't miss

Then open the attic up and let it air out for half an hour before you start anything. Work slow, bag as you go, and don't drag loose material across the joists.

Also, pay attention to where you're stepping. Attic drywall won't hold a person, and we wrote about that in is your attic floor safe to walk on.

One more thing, and it's the part almost everybody skips. Seal the entry points, either before you clean or right after. Otherwise you'll be up there doing all of this again in eighteen months.

We're a junk and demolition crew, not a pest company, so here's the straight answer: get a pest guy out to find the holes. Finding them is a real skill, and they're fast at it.

What an attic cleanout costs when rodents got there first

A regular attic full of boxes and old junk in the Treasure Valley usually runs $350 to $900, depending on how much comes out and how bad the access is.

Add contaminated insulation and you're in a different conversation. Figure roughly $1.50 to $2.50 a square foot to pull and bag old blown-in, so a 1,200 square foot attic lands somewhere between $1,800 and $3,000 before any new insulation goes back.

Why the jump? It's slow, hot work in a crawl-height space with respirators on, and every bag goes straight to the Ada County landfill.

None of it gets donated to Idaho Youth Ranch. Nothing gets sorted at Western Recycling. It's disposal, start to finish.

Yes, we'd love the job. But if you're looking at one corner of droppings and a dozen dry boxes, that's a Saturday morning with a mask and some bags.

Save your money for something else. When the insulation's soaked through and the smell has moved downstairs, that's when an attic cleanout crew earns the check.

The bottom line

Mouse droppings don't ruin an attic. They just mean you work wet, bag more than you planned on, and probably say goodbye to the insulation.

Seal the holes first so you're only doing this once.

If you're standing up there right now trying to figure out how bad it is, call us at (208) 593-2877. Send a couple photos and we'll tell you honestly whether it's a DIY afternoon or worth handing off. We do attic cleanouts all over Boise, Meridian, Nampa, and the rest of the valley.