Opening Hours
Monday - Saturday 6:00am - 5:00pm | (619)779-5858| 2498 Roll Drive #1436, San Diego, CA 92154

What Are These Yellow Spots On My Windows

Can’t figure out what those yellow spots are?

Cleaning bee poop

I had a hard time too. Most window cleaners among themselves call it “bee pollen”, and while its partially true, that isn’t quite the whole story.

If you live in California, you’re certain to have noticed the numerous yellow-gold dots all over your car, windows, house siding and just about every surface outside. Especially here in San Diego, certain parts of the county such as La Jolla, up on Mount Soledad, have some homes that just get hammered with this stuff. On their cars, everywhere!

If you live here, you know exactly the spots I mean. During certain times of the year the dots appear in greater numbers and no matter where you park, you end up getting these on your car every day. They are also difficult to get off your car and windows; they seem to appear out of nowhere and dry hard almost instantly.

Like so many, I wondered what these mystery dots where. Since I see them all the time cleaning windows, I always assumed it was pollen.

At first I thought it may be something from the planes overhead since the airport in Downtown is pretty close by and stay’s very busy. After all, that would account for the patterns I noticed on other homes but NOT the ones in La Jolla. We have so many airports in San Diego…both civilian, commercial and military peppered all over the county that it very well could be from an aircraft.

Another fact I’d like to point out is this; not ONE time did I see a bee fly overhead when at the home in La Jolla, when the spots would like magic appear before my eyes! I mean, as fast as I cleaned the glass, right away…SPLAT! I look around…no bee’s are laughing!

I worked very close to the San Diego airport, and have clients at the Mira Mar base, North Island and Camp Pendelton. So my first attempt to figure out exactly what this stuff is was to ask them if they knew anything about it. They were a big help, and explained that any liquids that are coming out of any aircraft, commercial or military-are color coded. This wasn’t one of the colors either.

One of the things I noticed was that these spots appear in greater frequency in number more on the West side than any other area of a building. I continued to try and find the source but everything came up a dead end. I contacted county officials to determine if it was a pesticide or other chemical being carried by the wind  still no answers to this mystery.

(Of course, the client in La Jolla, the entire cul-de-sac on that streets’ houses- those spots were on ALL sides not just the west).

I came across an article that came out in the LA Times that figured it all out. An LA Times columnist named Ralph Vartabedian was on the same quest and he utilized more professional resources to solve this mystery. He had the dots analyzed by the agency that manages air quality in California and was able to solve this mystery!

Bee pollen or Bee poop

Cleaning Bee Poop

So what are those yellow-gold dots? In two words, bee poop. Yes, bees do poop and when you live in an area with LOTS and LOTS of bees, you ‘ll find these yellow-gold dots of the digested pollen the bees eat on pretty much everything that isn’t covered. Bees follow the same route (or flight plan) over and over when traveling to and from their hives, so some places get hit more than others.

So now the mystery is solved! These mystery yellow-gold spots are the waste droppings of bees. Want to avoid getting them on your car or windows? When you find an answer, please let me know.

Meanwhile, many of our customers have to deal with this problem and I am given the task of figuring out the most cost efficient means of removing them both for the customer and for our company.

We tried using the pressure washer. Tried using different soaps. Different abrasive scrubbers.  We tried different acids. Nothing worked.

What did work, and was surprisingly easy, was using pure water to clean with and a waterfed pole. Bingo. Now we have a method to take these spots off, and it only costs a tad more than it would for a typical window cleaning! Unfortunately for the homeowner, to do it themselves would require a significant investment to buy these tools.

**Update May 26, 2017

We’ve found something even better. quicker and more efficient.  Grade 0000 steel wool used to scrub on wet glass is what gets this crap off (pun intended) faster than purified water.

**Update October 1, 2017

If you have ever shopped at the 99 cent stores in California you know of this product: L.A.’s Totally Awesome This stuff worked faster than anything else including hydrochloric acid! Be warned: read the label first because it specifically says not to use it on glass (the danger is letting it dry on the glass…even a little bit of it dries on the glass and that glass will probably be toast. So keep the glass wet is the solution, by constant agitation with a sponge or equivalent.

Your welcome. =)



So, if you are reading this article and are not a professional window cleaner, ask your service provider if they use pure water cleaning. They should be able to take care of this problem for you. If you would like to make that investment and do it yourself, please give me a call (619)779-5858 and  I can walk you thru the process.

Happy window cleaning!