I've had some success with muriatic acid- although you have to be very careful & only works if stains not too deep. They sell it in pool supplies.
Windex contains ammonia and surfactants that help break down and lift away dirt and grime from surfaces. The ammonia helps to dissolve grease and grime, while the surfactants help to loosen dirt so it can be wiped away easily. When sprayed on a stain, Windex helps to break it down and make it easier to clean off surfaces.
To clean salt stains off nubuck shoes, gently brush off any excess salt using a soft brush. Then, mix a solution of equal parts water and vinegar and wipe the stained areas with a cloth dampened with this mixture. Allow the shoes to air dry and then brush the nubuck to restore its texture.
To remove salt stains from windows, mix equal parts of white vinegar and water and apply the solution to the stains using a clean cloth or sponge. Let it sit for a few minutes, then wipe it off with a clean cloth. Repeat if necessary until the salt stains are removed.
To clean dried cement off a porcelain sink, you can try using a mixture of warm water and white vinegar to soften the cement. Apply the solution to the affected area and let it sit for a few minutes before scrubbing gently with a sponge or soft-bristled brush. Rinse thoroughly with water once the cement is removed.
Detergents contain molecules called surfactants that trap dirt and oils from clothes in the water, allowing them to be rinsed away. The surfactants in the detergent surround the dirt particles and lift them off the fabric, suspending them in the water to be washed away. This helps to remove stains by making them easier to lift off the fabric during the washing process.
I heard baking soda and warm water works.
If you've already tried washing it with soap and water, then try an eraser. Regular kind or the Mister Clean Eraser thingy.
To clean dirt off sandals, start by shaking them to remove loose debris. For stubborn dirt, use a soft brush or cloth dampened with water to scrub the affected areas gently. If needed, a mild soap can be added to the water for tougher stains. Finally, rinse them with clean water and let them air dry thoroughly.
so you can clean the stains off your clothes
bleach and ammonia
Gently, with water.
If you were to use brake cleaner it will clean all the dirt and oil off of it.
Sandblasting beads are small glass bead with no holes. They are sprayed by a sandblasting gun at very high speeds at metal to clean off rust or paint the same way you can use a pressure washer to clean dirt, loose paint and stains from a wooden deck.
Ketchup and a sauce pad.
Bit of spit and a rub
Windex contains ammonia and surfactants that help break down and lift away dirt and grime from surfaces. The ammonia helps to dissolve grease and grime, while the surfactants help to loosen dirt so it can be wiped away easily. When sprayed on a stain, Windex helps to break it down and make it easier to clean off surfaces.
If your pool filter is up and running, also it is best to clean the walls and floor if you have a normal to high chlorine level because this will be also your cleaning agent. Take a soft bristle brush, get in the pool and start cleaning, all the above should come off. it is better if the filter is running so you can vac out the dirt, when the dirt goes to the bottom of the pool.