The phrase "a dirty spot" is correct and usable in written English.
It can be used to describe a location or area that is unclean or stained.
Example: "I noticed a dirty spot on the kitchen floor that needs to be cleaned."
Alternatives: "a soiled area" or "a stained patch."
The hand sticking out of it is so you know it's quicksand and not just a dirty spot on the flag.
There is even an eye-catching tactic that Collegiate is calling reverse graffiti: The theme and logo of the campaign, "Positive and inclusive," along with the church's Web address, are power-washed into a dirty spot on a sidewalk, usually near a phone kiosk or bus shelter displaying a poster from the campaign.
When the Fukitorimushi finds a dirty spot, it lights up red, starts rubbing the dirt away and moves on.
Who wants to practice in a dirty spot?
What happens when a dirty spot becomes a stubborn stain, not capable of being washed away simply with your homemade granite cleaner?
Most of the time the mess is concentrated to a small area, something that Becca credits to a feature that leads the Roomba to go over an area repeatedly if it thinks it has detected a particularly dirty spot.
If there is a particularly dirty spot, you can go back over it once you have cleaned it once.
He set the market-place with plane-trees; and the Academy, which was before a bare, dry, and dirty spot, he converted into a well-watered grove, with shady alleys to walk in, and open courses for races.
If your guinea pig only has one or a few dirty spots (such as on his rump) you can use a wet washcloth to wipe the dirt away.
Sprinkle some cornstarch over the dirty spot and use a fur comb to work out the dirt.
It charges itself and finds its own way around, and even lets you know via LED when it's found an extra-dirty spot that needs a little extra inchworming across.
