TL;DR
A colander feels greasy after washing because the film is not in the bowl, it is in the holes. Every perforation has a rim where oil, starch, and dish soap residue collect and where a sponge never makes contact. Wash it with hot water and a brush pushed through from the inside, and rinse from the outside so residue exits rather than smearing.
Why the holes are the problem
A colander is mostly edge. A twelve-inch colander can have several hundred perforations, and each one has an inner wall a sponge cannot reach. Pasta water carries starch and any oil in the pot, and both settle onto those walls as the water drains through.
Starch dries into a slightly tacky film. Oil dries into a slick one. Together they feel exactly like a colander that "will not come clean."
Plastic makes it worse. Plastic is slightly porous compared to steel and it holds oil in a way stainless does not, which is why an old plastic colander can feel greasy the moment it dries even after a proper wash. The same issue shows up on plastic bowls, covered in how to clean mixing bowls.
Perforated tools are their own category, and our guide to cleaning kitchen tools without damaging them covers why the hole rim, not the bowl, is always the part that stays dirty.
What is the right way to clean a greasy colander?
Wash it in water as hot as you can stand with plenty of dish soap, pushing a dish brush through the holes from the inside face. Then rinse under hot running water from the outside, so loosened residue exits rather than being driven back through. Air dry upside down.
Direction matters
Food and water traveled from the inside out. That is the direction the residue is packed, so brushing from the inside pushes it out along the same path.
Rinsing is the reverse. Rinse from the outside, and water pushes the loosened film back out through the inside face, where it drops away. Rinsing from the inside pushes it into the hole rims you just cleared.
It sounds fussy for a colander. It is the difference between one wash and three.
Water temperature does most of the work
Oil is the actual problem, and the single biggest factor in removing oil is water temperature. Hot water plus detergent breaks up a fat film in a way that lukewarm water simply does not.
Run the tap hot, or fill a basin with hot water and let the colander sit in it for a few minutes before scrubbing. Detergent needs contact time as well as heat.
For a colander that is genuinely greasy from draining fried food or fatty stock, a ten to fifteen minute soak in hot soapy water first makes the scrub trivial. Do not stretch a soak overnight -- standing food-soiled water grows bacteria and is bad for any riveted joint.
Fine mesh strainers need a different approach
A fine mesh strainer is not a colander with smaller holes. The mesh is a woven screen, and it dents, stretches, and tears.
Never scrub mesh with force or use a stiff wire brush. Instead, hold it upside down under a strong hot stream so water pushes debris back out the way it came, then work a soft brush across the outside face only.
For a strainer clogged with something sticky like puree or nut butter, a soak in hot soapy water and then a soft brush is the whole method. A bent section of mesh never sits right afterward and leaks solids past it permanently. The same care applies to how to clean a flour sifter and a fine mesh sieve.
Material rules
Stainless steel. The easiest. Hot soapy water, brush, rinse, dry. Avoid chlorine bleach, which pits stainless steel, and avoid steel wool, which leaves iron particles that rust in place.
Plastic and silicone. Holds oil and stains from tomato and turmeric. Wash hot with plenty of detergent. A baking soda paste helps with staining. Do not use abrasive powders, which scratch the surface and give oil more to hold onto.
Enamel-coated. Treat gently. A chipped enamel colander exposes the steel underneath, which then rusts, and a chipped edge is a food-safety and injury concern. Replace it rather than scrubbing harder.
Aluminum. Uncoated aluminum discolors in alkaline dishwasher detergent and pits with acid. Hand wash it.
Drying and storage
Stand the colander upside down or on edge so water leaves the holes and the rim fold. Water sitting in a rolled rim is the reason otherwise fine colanders develop dark seeps and odor.
Give it fifteen minutes of air before nesting it inside another bowl. Stacking wet is how the underside stays damp and how odor develops in a cabinet.
If a plastic colander has developed a smell that survives a hot soapy wash, scrub it with a baking soda paste, rinse hot, and dry it in open air. If the smell persists in an old, scratched plastic colander, the surface is likely too scored to clean reliably and replacement is the practical answer. Source: FDA Food Code guidance on cleanable food-contact surfaces.
For the broader routine on small tools, see cleaning kitchen tools without damaging them, and our house cleaning services page covers where kitchen detail sits in a full clean.
FAQ
Why does my colander still feel greasy after washing?
The oil film is inside the holes, not in the bowl, and a sponge never touches those inner walls. Wash with very hot water and plenty of dish soap using a brush pushed through from the inside face, then rinse from the outside so residue exits instead of being pushed back in.
How do you clean a fine mesh strainer without wrecking it?
Hold it upside down under a strong hot stream so water pushes debris back out the way it entered, then brush only the outside face with a soft brush. Never scrub woven mesh hard or use a wire brush, since a dented or stretched section leaks solids past it permanently.
Can a colander go in the dishwasher?
Stainless and most plastic colanders are dishwasher safe, though the spray does not fully clear oil from hole rims, so a heavily greasy one still needs a hand wash. Uncoated aluminum should be hand washed, because alkaline dishwasher detergent discolors and pits it.
How do you get tomato stains out of a plastic colander?
Wash it hot with dish soap first, then scrub the stained areas with a baking soda paste and rinse. Some staining is permanent, particularly on older scratched plastic. Staining is cosmetic and is not a reason to use bleach or abrasive powders, which damage the surface further.
Why does my colander smell?
Usually water and residue trapped in the rolled rim or under a riveted handle, or oil held in scratched plastic. Brush along the rim and rivets, wash hot with detergent, and dry the colander upside down in open air rather than nesting it wet inside another bowl.
Small kitchen items are the ones that quietly stay dirty. If you would rather hand the whole space off, every home is different, so the real number depends on size, condition, and what you want covered. Get a quote and we will walk you through it.