How can I deep clean my washer after a major "biohazard" mess?

You definitely don't need to scrap the machine, but you do need to do a manual pass before you trust the self-clean cycles. If there is visible residue left in the drum, put on some gloves and wipe it out with paper towels first. If you have a front-loader, pull back the rubber door gasket and clean inside those folds, as that’s where the gross stuff loves to hide. For a top-loader, check if the agitator unscrews; sometimes gunk gets trapped underneath the plastic base and causes a lingering smell.

Once the physical debris is gone, run the hottest cycle the machine offers—usually labeled as 'Sanitize' or 'Tub Clean'—and use a full cup of **liquid chlorine bleach**. Don't be stingy with it. The combination of high-temprature water and bleach is extremely effective at breaking down organic matter and killing bacteria like E. coli. If the smell is still there after one round, do a second cycle using an oxygen-based cleaner or a dedicated washing machine tablet to strip away any remaining biofilm.

The dryer is actually easier to handle becasue the sustained high heat is a natural disinfectant. To put your mind at ease, grab some disinfecting wipes or a rag with a diluted bleach solution and wipe down the entire drum, the inside of the door, and the handle. Clean out the lint trap thoroughly, then run the dryer on high heat for about 30 minutes while empty. That will effectively sanitize the interior and kill off anything the wipes missed.

It feels overwhelming right now, but remember that washers have been dealing with cloth diapers and sick-room bedding for a hundred years. It isn't nuclear waste; it's just organic material that dissolves with the right chemicals and temperature. After you finish the cleaning cycles, run a load of old rags or a sacrificial towel. If those come out smelling fresh and looking clean, the machine is officially safe for your regular clothes again.

I've dealt with this after a bad stomach bug hit my house. One thing people forget is the drain pump filter if you have a front loader. I found a bunch of gunk stuck in mine that the bleach cycles couldn't reach, and that was the source of the 'phantom' smell for a week. Also, don't forget to wipe down the exterior knobs and the lid or door frame. If your dad's hands were messy, he probly touched the start button and the detergent tray handle. A spray bottle with 70% alcohol worked wonders for me to get those spots without ruining the finish.

You also need to meticulously inspect the detergent dispenser drawer and its surrounding housing, as the violent agitation process inherent in a heavily soiled load can frequently cause aerosolized particulates or contaminated splash-back to infiltrate the upper internal recesses where the water inlet jets reside. If your unit is a front-loader, I'd strongly advise removing the drawer assembly entirely to verify that no organic matter has been forced into the siphon channels, which would effectively serve as a reservoir for bacterial proliferation and ensure a persistent olfactory nuisance regardless of how many bleach cycles you initiate. People often forget that the detergent path isn't strictly a one-way street during high-speed agitation.

Spot on with the manual cleaning first. One tiny thing to add: check the moisture sensor bars inside the dryer drum. They’re usally two small metal strips right near the lint housing. If any residue or film got on those, it can trick the dryer into stopping early or just keep the smell lingering even after you wipe the drum. I’d give them a quick swipe with a cotton ball dipped in rubbing alcohol. It’s a 10-second job but ensures the sensors actually work right after such a gross load. Better safe than sorry when you’re trying to get that sanitized peace of mind.

Honestly, even after the bleach, you shoud run a cycle with Affresh Washing Machine Cleaner tablets. Bleach kills the bacteria, but Affresh is specifically formulated to strip away the actual gunk and film that holds onto the scent. I’ve used it after some pretty gnarly pet accidents and it’s the only thing that worked. For the dryer surfaces, hit the handle and the drum with some Lysol Disinfectant Spray once you’ve wiped it down. It’ll give you that final peace of mind that the area is actualy sanitized.

Quick update—the washer is finally back in action. Wiping the drum out by hand was gross, but the suggestion about the detergent drawer was a lifesaver; I found some nasty splash-back hidden in there. After two hot cycles with bleach and cleaning the moisture sensor bars in the dryer, the smell is totally gone. Feeling way less panicked now. Thanks for the help, everyone!