Once you’ve cleaned hundreds of thousands of window panes, you start to be able to identify the different types of muck that builds up on windows. Local window cleaner, Ben (who lives in Cleckheaton), dishes the dirt on what’s mucking up your windows.
Bird poo
This is one of the most common and visible types of dirt you'll find on your windows. We start to see it often around March. Cleckheaton has lots of trees and this attracts birdlife. Local species include house sparrows, blackbirds and chaffinches, but we have customers near the Chainbar roundabout who have swifts nesting in their soffits. Larger birds like gulls have become more common in the area - you can hear their tell-tale “mew” over the industrial units near the M62. In April 2025, someone spotted a Pallid Harrier over Cleckheaton town centre.
With lots of birds around - that translates to your glazing getting a splattering.
If it's hot and sunny (Cleckheaton gets around 1,336 hours of sunshine each year), then the bird mess will bake onto the glass - which makes it harder to remove. Sometimes, all we have to do is give it a pre-soak prior to scrubbing, other times bird guano will require us to use a scraper to mechanically remove it.
Bee poo
One of the hardest substances to remove from the surface of glass is bee poo.
Bees eat pollen and this makes up a major component of their plops, as does pollen fat and grains. Bee poo is a bright, golden-yellow colour and typically measures around 3-6mm on a window. Cleckheaton sees lots of native bee types, including bumble bees, mason bees and even honey bees - with known hives in Gomersal, Birkenshaw and Scholes.
Bee poo is very stubborn, sometimes we'll need to use a scrub pad (or scraper) to clean heavily soiled windows.
Atmospheric dust
Just like your TV screen in your home, windows attract a film of dust. Cleckheaton sees lots of building work, from the several large construction projects happening in Whitechapel, Merchant Fields, Kenmore and Rawfolds. Add to that, the dry spell we had during March/April 2025 and homeowners having extensions or garden building projects completed - it’s no wonder windows get dusty. Stihl saws are one of the worst offenders - no one ever seems to hook them up to a water supply to keep the dust down.
Traffic kicks up fine particles too, with the turbulence generated by vehicles (like the busy Bradford Road), throwing the particles way up into the air. This eventually settles on sills or clings to the glass on your window. Gritting covers the roads with de-icing agents like salt, which when mixed with water, and churned up by cars, turn into an airborne mist that can settle on windows. We find that a fair bit when the temperatures fall, during December, January and February. This is why we recommend year-round cleaning - dirt isn’t just a summer problem.
We even have Saharan dust sometimes in Cleckheaton. This happened in March 2025 - it was most noticeable in the morning as a film on your car windscreen, or on the numerous velux windows we clean for customers.
Traffic kicks up fine particles too, with the turbulence generated by vehicles (like the busy Bradford Road), throwing the particles way up into the air. This eventually settles on sills or clings to the glass on your window. Gritting covers the roads with de-icing agents like salt, which when mixed with water, and churned up by cars, turn into an airborne mist that can settle on windows. We find that a fair bit when the temperatures fall, during December, January and February. This is why we recommend year-round cleaning - dirt isn’t just a summer problem.
We even have Saharan dust sometimes in Cleckheaton. This happened in March 2025 - it was most noticeable in the morning as a film on your car windscreen, or on the numerous velux windows we clean for customers.
Hair strands
Hairs end up on windows quite often. It seems many people drop loose hair strands, perhaps removed from a hairbrush, out of their window, which then sticks to the glass. Cats like to jump on window sills and their hairs stick to the glass. The 2021 census listed Cleckheaton’s population as 17,187 - and with studies showing 24% of UK adults owning a cat - there could potentially be 4,125 cats in Cleck.
Spiders
Spiders seem to be active between March, till late October. It’s very common to find a small nest in the top corner of your window frames. Typically, we see that it is Giant House Spiders (Tegenaria Gigantea) on the windows of Cleckheaton households - but it’s also common to see Missing Sector Orb-weavers (Zygiella x-notata), though the UK has lots of other types.
In our experience, spiders love to build webs right in the nook of the beading of windows. To them, it makes the perfect place to create an egg sac. But we also find them hanging out on trickle vent covers and the crevices around UPVC trim. They also build webs around patio door hinges and between the frame and the sill of doors.
Leaves and sap
Trees are another contributor to dirty windows.
Sap is a sticky substance that falls from trees and can end up being blown onto your glass.
See this video of sap falling from sycamore trees.
Because sap is very sticky - dust will stick to it, so it makes your window even more dirty.
Cleckheaton, when viewed from above, has lots of trees. In fact, hundreds of years ago, maps showed the Spen Valley area as a heavily wooded forest.
We still have lots of English Oak, Sycamore, Ash and Horse Chestnut trees around, often very close to houses.
Leaves make a mess too, with sycamore and ash dropping what people call “helicopter leaves”. These drop onto sills and gather up, encouraging more dirt and mess to collect.
Pets and children
We find some of the worst culprits for making windows dirty are children and pets.
Dogs often leave muddy pawprints on the threshold of doors, as well as excitedly jumping up at windows and doors. Kids love to play and that means we often see mucky handprints on glass or marks where they’ve kicked a football onto a window. Also, people often open doors using the glass, leaving fingerprints behind.
BBQ's & fires
Remember how we said Cleckheaton gets over 1,300 hours of sunshine a year? Naturally, people want to get out and enjoy that. So they have friends around and chuck some steaks bought from a local farm shop on the barbie and have a good time.
The only problem is that people position the BBQ near to, or downwind of, their windows. Smoke, soot and atomized cooking grease can travel to the glass and make them mucky. Chimneas and firepits do the same.
If you do like a BBQ, try to move it away from your house if you can. Or as Hank Hill, from King of the Hill says - switch to propane, so you can “taste the meat, not the heat”.
Paint
So many times we come across paint on the windows of Cleckheatonians. People typically seem in a rush to get their painting done and masking up windows is neglected. We’ve seen garden paint splashed all over UPVC, wood treatment splattered across the glass and even stubborn gloss paint from ironwork or handrails on the building.
All examples given are based on common experiences encountered while window cleaning in Cleckheaton and surrounding areas. No specific individuals or businesses are implied.