How to wash dirty car ?

[sshazam]

Hello all,

The car hasn't been washed in 4+ weeks so it's accumulated a fair amount of dirt.

First hit it with warm water and DG901 in my foam cannon followed by two passes washing by hand with DG901 as well. To my surprise i'm still finding stubborn caked on dirt in certain areas. On the bottom sills theres some mud splatter that isn't coming off no matter how hard I try. I have a fairly powerful pressure washer as well so it's not a lack of pressure.

I also plan on polishing the car in a few weeks and didn't want my pad to gum up with mud etc.
My next thought was to use hot water (obviously not boiling water)

I'm not sure if theres any deeper cleaning soaps or what other options I could try ?

[Setec Astronomy]

Are you saying you used the foam cannon on the "mud splatter", or used the pressure washer alone? I find it hard to believe a pressure washer isn't removing mud splatter (or the subsequent hand wash--what kind of wash media are you using?). So, are you sure it's mud and not tar, road paint, etc.?

[Desertnate]

If it's mud, the temperature of the water won't change the results. To expand on Setec's questions above, could it be cement or clay mud which would be harder to remove than regular road spatter. What ever it is, you've got to get it off before you start polishing. I'm surprised a good blast for a pressure washer wouldn't take care of the problem.

[Setec Astronomy]

Oh, cement...why'd it have to be cement...I didn't think of cement.

[ViperGuy21]

If it's mud/dirt/grime maybe try some APC or degreaser? I don't see how a pressure water and washing wouldn't get that off however...
But if it's cement, I have no clue

[sshazam]

Are you saying you used the foam cannon on the "mud splatter", or used the pressure washer alone? I find it hard to believe a pressure washer isn't removing mud splatter (or the subsequent hand wash--what kind of wash media are you using?). So, are you sure it's mud and not tar, road paint, etc.?

It's just random dirt sections all over the car. So on the around the wheel arches/lower parts of the car it looks like mud. On other parts it's just general dirt/contamination thats not coming off. I used my foam cannon first to help loosen up the dirt then rinsed the car with my pressure cleaner. Followed by two passes off washing the car with the two bucket method. I live in Australia so the car has been left in the sun for 4+ weeks. I think it's etched into the paint or something.


If it's mud, the temperature of the water won't change the results. To expand on Setec's questions above, could it be cement or clay mud which would be harder to remove than regular road spatter. What ever it is, you've got to get it off before you start polishing. I'm surprised a good blast for a pressure washer wouldn't take care of the problem.
I think i'ts clay mud around the lower trim/wheel arches and just general road contamination on other areas. 95% of the car is clean just small random sections off bugs, dirt and mud on other parts. Thats been left unwashed for 4 weeks and baking in the Australian sun.


If it's mud/dirt/grime maybe try some APC or degreaser? I don't see how a pressure water and washing wouldn't get that off however...
But if it's cement, I have no clue
It's not cement. Looks like it's bugs/dirt/clay mud or something like that.
Is APC safe to use on paint ? What kind of ratio would I use ?

Thanks for the help everyone, I really appreciate it.

Let me clarify my original question better.

My cars been parked outside and hasn't been washed for 4+ weeks. When I came back from my trip I washed it but found on certain section there was dirt I couldn't remove no matter how hard I tried. It's just bits of grime, bugs and what looks like dried on mud/clay.

- Sprayed the car with my foam cannon attached to my pressure cleaner with warm water and DG901
- Rinsed car with my pressure cleaner
- 2 bucket method x2 passes with the two bucket method.
I'm lucky my car is silver and hides swirls incredibly well so I can get aggressive. It's stuff where I can use my finger nail (Gasp! bet some of you just felt sick at that thought :p) to scrape it off but the mud like substance was a bit more stubborn.

[Desertnate]

You can try a good APC to see if that will help. A good bug remover will help on the dead bugs. For the clumps of mud/clay, you may have to rub on them with your hand to get that stuff loose. A clay bar is always an option too for areas that aren't clumps of mud.

For the areas on horizontal panels, you could try wetting a towel and then laying it over those areas and let it slow soak that way. It might soften things up