TL;DR
A bin draws pests for two reasons: food residue and standing moisture. Rinse anything that held food before it goes into recycling, use a liner that actually fits so the bin walls stay clean, and wash the bin and its lid gasket every month or two. Drying the bin completely before the next liner goes in matters as much as washing it, because a damp film is what flies breed in.
What actually attracts pests to a bin
It is not the trash itself so much as the film left behind. A leaking bag, a rinsed-but-not-really jar, a drip that runs down the inside wall -- all of it dries into a sugary or greasy layer that stays there through every bag change.
Fruit flies do not need much. A thin film in a bin seam or under a lid rim is enough to complete a life cycle. Ants follow sugar. Cockroaches follow grease and moisture together, and they favor the dark gap between a bin and a cabinet wall.
Rodents are drawn from further out, usually to an outdoor bin with a loose lid or a bag left beside it.
Source: Municipal solid waste and public health sanitation guidance
How do you keep a trash can from smelling and drawing bugs?
Rinse food containers before they go in, use a liner sized to the bin so nothing runs down the sides, take out the bag before it starts to smell rather than after, and wash the bin and lid gasket every four to eight weeks. Dry it completely before the next liner goes in.
Liner discipline is the cheapest fix
A liner that is too small folds down into the bin, and the folds channel drips straight onto the bin wall. A liner that fits and folds over the rim keeps almost all of the mess inside the bag.
Double-bag anything wet -- meat trays, bones, a takeout container with sauce in it. That one habit prevents most of the leaks that produce the film.
Do not overfill. A bag stretched past the rim tears at the corner when you lift it, and a tear at the bottom of a bin is the worst possible place for it.
Change the bag on a schedule rather than on a smell. If a kitchen bin smells, the film is already established, and a bag change will not remove it.
Rinse recycling, and let it dry
Recycling is the surprise offender. People rinse a jar, drop it in wet, and the bin turns into a humid box of sugar residue. Rinse, then let containers drain before they go in.
Anything that held something sweet -- juice, soda, sauce, wine -- deserves a real rinse, not a swish. A sticky can in a warm bin is a fruit fly nursery, which is the same failure mode described in where fruit flies come from in a clean kitchen.
Flatten and stack cardboard rather than piling it loose. Corrugated cardboard is a favorite harborage for cockroaches, and a damp stack in a garage corner is exactly what they want.
Washing the bin
Take the bin outside or into a tub. Empty it, then wash the inside and outside with hot water and dish soap and a long-handled brush. Get the bottom corners and the underside of the rim, which are the two spots that always get skipped.
Rinse well, then dry it fully. Standing water in the bottom of a bin is a breeding site on its own, and it makes the next liner stick and tear.
If the bin still smells after washing, the odor is usually in scratched plastic. A dilute bleach solution can be used on a bin, but only after the soap wash and rinse, and only with ventilation. Never combine bleach with an ammonia-based cleaner, an acidic cleaner, or rubbing alcohol -- the details are in cleaning products you should never mix. The full step-by-step is in how to clean trash and recycling bins.
The lid, the gasket, and the pedal
A step-can pedal mechanism collects drips underneath, where nobody looks. Tip the bin and check.
Lid gaskets on odor-sealing bins hold a ring of residue that becomes the smell people blame on the bag. Pull the gasket if it comes out, wash it, and dry it before it goes back.
For an outdoor cart, the lid has to close flat. A cracked lid or a warped rim is an open invitation to raccoons and rodents, and most waste haulers will replace a damaged cart.
The floor around the bin
Pull the bin out and clean under and behind it. A cabinet bin sits in a dark, enclosed space with a hard floor, and crumbs and drips accumulate there for months.
Wipe the cabinet floor and the back wall, and check for a soft or stained spot, which means something leaked and stayed wet. That whole category of neglected residue is covered in why crumbs and cooking grease attract pests.
The sink drain nearby is part of the same system. A garbage disposal builds a biofilm under the splash guard that smells and feeds drain flies -- see how to clean a garbage disposal.
Outdoor carts
Keep carts on a hard surface, not on grass or bare dirt, and away from the house wall if you can.
Bag everything before it goes in the cart. Loose food waste in a cart is what brings rodents into a yard in the first place.
Rinse an outdoor cart a few times a year, more in warm weather, and let it dry with the lid open in the sun. Never rinse a cart into a storm drain if it has food residue in it; wash it on grass or gravel where the water soaks in.
If you see droppings, chew damage, or a nest near the carts, that is a job for a licensed pest control operator, not a cleaning routine.
FAQ
How often should you clean a kitchen trash can?
Wash the bin itself every four to eight weeks, and wipe the lid and rim weekly since that is where residue collects fastest. If a liner leaks, wash it immediately rather than waiting for the schedule. Dry the bin fully before the next liner goes in.
Why does my trash can smell even after I take the bag out?
Because the smell is in the film on the bin walls, not in the bag. Leaks and drips dry into a layer that stays through every bag change. A hot water and dish soap wash with a brush, including the bottom corners and under the rim, is what removes it.
Do you really need to rinse recycling?
Yes, for anything that held food or a sweet drink. Residue in a warm bin is what draws fruit flies, ants, and roaches, and it is the reason a recycling bin often smells worse than a trash bin. Rinse, then let containers drain before they go in.
What keeps rodents out of an outdoor trash cart?
A lid that closes flat, everything bagged before it goes in, and nothing left on the ground beside the cart. Keep the cart on a hard surface rather than dirt. A cracked or warped lid should be replaced, and most waste haulers will swap a damaged cart.
Can you put bleach in a trash can to kill the smell?
You can use a dilute bleach solution after washing with soap and rinsing, with the bin outdoors or in a well-ventilated space. Never combine bleach with ammonia-based cleaners, acids like vinegar or descalers, or rubbing alcohol. Soap and a brush do most of the work anyway.
Why are there small flies around my kitchen bin?
Almost always a residue film or a damp spot rather than the trash itself. Check the bin seams, the underside of the lid rim, the cabinet floor under the bin, and the sink drain nearby. Removing the film and drying the area ends the cycle within days.
Bins, cabinet floors, and the corners around them are exactly the spots a routine clean is meant to cover. If you want that handled on a schedule, get a quote or read more about house cleaning services.